Peptidyl inhibitors of viral proteases

ABSTRACT

The invention provides amino acid derivatives of the formula ##STR1## wherein E represents CHO or B(OH) 2  ; 
     R 1  represents lower alkyl (optionally substituted by halo, cyano, lower alkylthio, aryl-lower alkylthio, aryl or heteroaryl), lower alkenyl or lower alkynyl; 
     R 2  represents lower alkyl optionally substituted by hydroxy, carboxy, aryl, aminocarbonyl or lower cycloalkyl; and 
     R 3  represents hydrogen or lower alkyl; or 
     R 2  and R 3  together represent di- or trimethylene optionally substituted by hydroxy; 
     R 4  represents lower alkyl (optionally substituted by hydroxy, lower cycloalkyl, carboxy, aryl, lower alkylthio, cyano-lower alkylthio or aryl-lower alkylthio), lower alkenyl, aryl or lower cycloalkyl; 
     R 5  represents lower alkyl (optionally substituted by hydroxy, lower alkylthio, aryl, aryl-lower alkylthio or cyano-lower alkylthio) or lower cycloalkyl; 
     R 6  represents hydrogen or lower alkyl; 
     R 7  represent lower alkyl (optionally substituted by hydroxy, carboxy, aryl or lower cycloalkyl) or lower cycloalkyl; 
     R 8  represents lower alkyl optionally substituted by hydroxy, carboxy or aryl; and 
     R 9  represents lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower al koxycarbonyl, 
     and salts of acidic compounds of formula I with bases, which are viral proteinase inhibitors useful as antiviral agents, especially for the treatment or prophylaxis of infections caused by Hepatitis C, Hepatitis G and human GB viruses.

FIELD OF THE INVENTION

The present invention is concerned with amino acid derivatives and a process for their manufacture.

SUMMARY OF THE INVENTION

The amino acid derivatives provided by the present invention are compounds of the formula ##STR2## wherein E represents CHO or B(OH)₂ ;

R¹ represents lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;

R² represents lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and

R³ represents hydrogen or lower alkyl; or R² and R³ together represent di- or trimethylene optionally substituted by hydroxy;

R⁴ represents lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, lower alkenyl, aryl or lower cycloalkyl;

R⁵ represents lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl;

R⁶ represents hydrogen or lower alkyl;

R⁷ represent lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl;

R⁸ represents lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl; and

R⁹ represents lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl;

and salts of acidic compounds of formula I with bases.

The compounds of formula I and their aforementioned salts inhibit proteinases of viral origin and are useful in the treatment of viral infections, particularly viral infections caused by Hepatitis C, Hepatitis G and the human GB viruses.

This invention also provides processes of producing compounds of formula I comprising: (a) when E is CHO, treating a corresponding acetal with a strong acid; or (b) when E is B(OH)₂, treating a corresponding dioxaborolane with a strong base or an alkali metal periodate.

DESCRIPTION OF THE FIGURES

FIGS. 1a-j--Nucleotide sequence of pMAL-NS3" Gly 12 NS4A plasmid (SEQ ID NO:1).

FIG. 2--Amino acid sequence of MBP-NS3"-gly 12-4A enzyme (SEQ ID NO:2).

Amino acids 1-391--Maltose binding protein and other sequences derived from New England Biolabs vector pMAL™-c2.

Amino acids 393-605 and 622-675--HCV-derived sequences (amino acids 1007-1219 and 1658-1711 of HCV polyprotein respectively).

Amino acids 606-621--linker region.

DETAILED DESCRIPTION OF THE INVENTION

This invention provides compounds of the formula ##STR3##wherein E is CHO or B(OH)₂ ;

R¹ is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl,heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;

R² is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and

R³ is hydrogen or lower alkyl; or

R² and R³ together are di- or trimethylene optionally substitutedby hydroxy;

R⁴ is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, loweralkenyl, aryl or lower cycloalkyl;

R⁵ is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl;

R⁶ is hydrogen or lower alkyl;

R⁷ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl;

R⁸ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl; and

R⁹ is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl,

and salts of acidic compounds of formula I with bases.

As used in this specification, the term "lower alkyl", alone or in combination, denotes a straight-chain or branched chain alkyl group containing 1-7, preferably 1-4, carbon atoms, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec.butyl, tert.butyl, n-pentyl, neopentyl and the like. "The terms "lower alkenyl" and "lower alkynyl" denote alkenyl groups preferably containing 2-7 carbon atoms, e.g. vinyl, allyl, n-propenyl, n-butenyl, and the like, and, respectively, alkynyl groups containing 2-7 carbon atoms, e.g. propargyl and the like. The term "lower cycloalkyl" denotes a cycloalkyl group containing 3-7 carbon atoms,e.g. cyclopropyl, cyclobutyl, cyclopentyl and the like. The lower alkoxy part of a "lower alkoxycarbonyl" group is a lower alkyl ether group in which the lower alkyl moiety has the aforementioned significance. The term "aryl" denotes a monocyclic or polycyclic aromatic hydrocarbon group, e.g.phenyl, naphthyl or the like which is unsubstituted or substituted by one or more substituents selected from e.g. lower alkyl, lower alkoxy, nitro, halo, halo-lower alkyl, hydroxy, acetamido and the like. The term "heteroaryl" denotes a 5- or 6-membered aromatic heterocyclic group which contains N, O and/or S as the hetero atom(s) and which is optionally benz-fused and/or substituted in the same manner as the aryl group definedabove. Examples of heteroaryl groups are furyl, thienyl, pyridyl, pyrimidinyl, benzofuranyl, benzothienyl, quinolyl, isoquinolyl and the like.

The compounds of formula I contain at least six asymmetric carbon atoms andcan therefore exist in the form of optically pure diastereoisomers, mixtures of diastereoisomers, diastereoisomeric racemates or mixtures of diastereoisomeric racemates. The present invention includes within its scope all of these possible forms.

One class of preferred compounds of formula I comprises those in which R¹ represents lower alkyl, halo-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl. Fluoro-lower alkyl is the preferred halo-lower alkyl group. Preferred heteroaryl-lower alkyl groups are thienyl-lower alkyl and furyl-lower alkyl. In a preferred embodiment of each of the embodiments of compounds of formula I described above, R² represents lower alkyl, lower cycloalkyl-lower alkyl or aryl-lower alkyl. In a preferred embodiment of each of the embodiments of compounds of formula I described above, R³ represents hydrogen. In another preferred embodiment of each of the embodiments of compounds of formula I described above, R² and R³ together represent trimethylene optionally substituted by hydroxy. In a preferred embodiment of each of the embodiments of compounds of formula I described above, R⁴ represents lower alkyl, lower cycloalkyl-lower alkyl, aryl-lower alkyl, aryl or lowercycloalkyl. In a preferred embodiment of each of the embodiments of compounds of formula I described above, R⁵ represents aryl-lower alkyl or lower cycloalkyl. In a preferred embodiment of each of the embodiments of compounds of formula I described above, R⁶ represents hydrogen. In a preferred embodiment of each of the embodiments of compounds of formula I described above, R⁷ represents lower alkyl, carboxy-lower alkyl aryl-lower alkyl or hydroxy-lower alkyl. In a preferred embodiment of each of the embodiments of compounds of formula I described above, R⁸ represents hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl. In a preferred embodiment of each of the embodiments of compounds of formula I described above, R⁹ represents lower alkyl-carbonyl or carboxy-lower alkylcarbonyl.

Examples of these preferred compounds in which E represents CHO are:

2(S)- N- N- N- N- N-(3-Carboxypropionyl)- L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!butyraldehyde;

2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4-difluorovaleraldehyde;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde;

2 (R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-(methylthio)propionaldehyde;

2(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-(butylthio)propionaldehyde;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-pentenaldehyde;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-pentynal;

2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-hexynal;

3-(benzylthio)-2(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!propionaldehyde;

2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl! -2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-(2-thienyl)propionaldehyde;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-(3-thienyl)propionaldehyde;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-3-(2-naphthyl)-D-alanyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-seryl-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-5 trifluorobutyraldehyde;

2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!hexanal;

(Z)-2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-g lutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-hexenal;

2(RS)- N- N- N- N- N-(benzyloxycarbonyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-4-chloro-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde;

2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-5-methylhexanal;

2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-5-hexenal;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-norleucyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde;

2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-2-cyclohexylglycyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde; and

2(RS)- N- N- N- N- N-(4-acetamidobenzoyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde;

and examples of these preferred compounds in which E represents B(OH)₂are:

1(RS)- N- N- N- N- N-(3-Carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!propylboronic acid;

1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!butylboronic acid;

1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-butenylboronic acid;

1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-4-chloro-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-butenylboronic acid;

1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanyl!amino!-3-butenylboronic acid;

1(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!pentylboronic acid;

1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucyl!amino!propylboronic acid;

1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-L-2-cyclohexylglycyl!-3-methyl-L-valyl!-L-leucyl!amino!propylboronic acid; and

1(RS)- N- N- N- N- N-(benzyloxycarbonyl)-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl-L-leucyl!-amino!propylboronic acid.

This invention provides a process for producing a compound of the formula: ##STR4##wherein E is CHO;

R¹ is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl,heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;

R² is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and

R³ is hydrogen or lower alkyl; or

R² and R³ together are di- or trimethylene optionally substitutedby hydroxy;

R⁴ is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, loweralkenyl, aryl or lower cycloalkyl;

R⁵ is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl;

R⁶ is hydrogen or lower alkyl;

R⁷ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl;

R⁸ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl; and

R⁹ is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl;

which process comprises treating an acetal of the formula ##STR5##wherein any carboxy, hydroxy or aminocarbonyl group present in the acetal is protected, and R¹⁰ and R¹¹ are each independently a lower alkyl; with a strong acid, thereby producing the compound. A further embodiment of this process comprises treating the compound of formula I asproduced by the above process, wherein the compound is acidic, with a base,thereby producing a salt of the compound. In an embodiment of the process described above, the acetal of formula II is bonded to a solid phase peptide syntheis resin.

This invention provides process for producing a compound of the formula ##STR6##wherein E is B(OH)₂

R¹ is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl,heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;

R² is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and

R³ is hydrogen or lower alkyl; or R² and R³ together are di-or trimethylene optionally substituted by hydroxy;

R⁴ is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, loweralkenyl, aryl or lower cycloalkyl;

R⁵ is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl;

R⁶ is hydrogen or lower alkyl;

R⁷ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl;

R⁸ represents lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl oraryl-lower alkyl; and

R⁹ is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl;

which process comprises treating a substituted dioxaborolane of the formula ##STR7##wherein any carboxy, hydroxy or aminocarbonyl group present in the dioxaborolane is or is not protected, and Q is ##STR8##wherein R¹², R¹³, R¹⁴ and R¹⁵ each are hydrogen or lower alkyl and R¹⁶ and R¹⁷ each are hydrogen or lower alkyl, with a strong acid when Q is (a) and with an alkali metal periodate when Qis (b) thereby producing the compound. A further embodiment of this processcomprises treating the compound of formula I as produced by the above process, wherein the compound is acidic, with a base, thereby producing a salt of the compound. In an embodiment of the process described above, theacetal of formula II is bonded to a solid phase peptide syntheis resin.

More specifically, the compounds of formula I hereinbefore and salts of acidic compounds of formula I with bases are manufactured by

a) for the manufacture of a compound of formula I in which E represents CHO, deacetalizing and, where required, deprotecting an acetal of the general formula ##STR9##wherein R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ have the significance given earlier, provided that anycarboxy, hydroxy and/or aminocarbonyl group(s) present is/are in protected form, and R¹⁰ and R¹¹ each represent lower alkyl, or

b) for the manufacture of a compound of formula I in which E represents B(OH)₂, ring opening and, where required, deprotecting a substituted dioxaborolane of the general formula ##STR10##wherein R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ have the significance given earlier, provided that anycarboxy, hydroxy and/or aminocarbonyl group(s) present may be in protected form, and Q represents a group of the formula ##STR11##wherein R¹², R¹³, R¹⁴ and R¹⁵ each represent hydrogen or lower alkyl and R¹⁶ and R¹⁷ each represent hydrogen or lower alkyl, and

c) if desired, converting an acidic compound of formula I obtained into a salt with a base.

Protected carboxy, hydroxy and aminocarbonyl groups which are present in the acetal starting materials of formula II and which may be present in the substituted dioxaborolane starting materials of formula III are carboxy, hydroxy and, respectively, aminocarbonyl groups protected with any conventional protecting group known from peptide chemistry. In particular, R², R⁴, R⁷, R⁸ and/or R⁹ can preferably represent tert-butoxycarbonyl-lower alkyl as protected carboxy,R², R⁴, R⁵, R⁷ R⁸ and/or R⁹ can preferably represent lower alkyl O-tert.butyl ether as protected hydroxy and R² can preferably represent tritylaminocarbonyl-lower alkyl as protected aminocarbonyl-lower alkyl.

The deacetalization of an acetal of formula II, preferably one in which R¹⁰ and R¹¹ each represent methyl, according to embodiment a) ofthe process according to the invention can be carried out using any conventional strong acid such as those described in T. W. Greene, P. G. M.Wuts, Protecting Groups in Organic Syntheses, 2nd edition, John Wiley & Sons 1991, in the presence of an inert organic solvent such as a halogenated aliphatic hydrocarbon, e.g. dichloromethane, and in the presence of water. Preferably the strong acid is trifluoroacetic acid or an equivalent strong acid Suitably, the deacetalization is carried out at about room temperature. When protected carboxy, hydroxy and/or aminocarbonyl groups are present in the acetal starting material, these are converted into free carboxy, hydroxy and/or aminocarbonyl groups underthe conditions of the deacetalization.

According to a variant of embodiment a) of the process according to the invention, an acetal starting material of formula II is bonded to a solid phase peptide synthesis resin. In one embodiment the starting material is bonded to a solid phase peptide synthesis resin as described in Example 4.In this case, cleavage from the resin takes place under the conditions usedfor the deacetalization.

The ring opening of a substituted dioxaborolane of formula III in which Q represents a group of formula (a), preferably one in which R¹², R¹³, R¹⁴ and R¹⁵ each represent methyl, according to embodiment b) of the process according to the invention can also be carried out using any conventional strong acid such as those described in T. W. Greene, P. G. M. Wuts, Protecting Groups in Organic Syntheses, 2nd edition, John Wiley & Sons 1991, in an inert organic solvent, e.g. a halogenated aliphatic hydrocarbon such as dichloromethane, and optionally in the presence of water. Preferably the strong acid is trifluoroacetic acid or an equivalent strong acid. Suitably, the ring opening is carried out at about room temperature. When protected carboxy, hydroxy and/or aminocarbonyl groups are present in the substituted dioxaborolane startingmaterial, these are converted into free carboxy, hydroxy and/or aminocarbonyl groups under the conditions of the ring opening.

The ring opening of a substituted dioxaborolane of formula III in which Q represents a group of formula (b), especially one in which one of R¹⁶and R¹⁷ represents hydrogen and the other represents methyl, accordingto embodiment b) of the process in accordance with the invention can be carried out in a conventional manner. Conveniently, the ring opening is carried out using any conventional periodate, especially an alkali metal periodate, especially sodium periodate in a buffered aqueous-organic medium, suitably at about room temperature. Advantageously, the medium consists of a mixture of an inert water-miscible organic solvent, e.g. acetone, and aqueous ammonium acetate. Any protected carboxy, hydroxy and/or aminocarbonyl group(s) present in the substituted dioxaborolane starting material are deprotected in a conventional manner known in the art e.g. by treatment with trifluoroacetic acid, prior to the ring opening.

According to a variant of embodiment b) of the process according to the invention, a substituted dioxaborolane of formula III in which Q represents a group of formula (a) is bonded to a solid phase synthesis resin. The bonding is typically through an alkyl group R¹², R¹³,R¹⁴ or R¹⁵ linked to the resin via an amide bridge. Cleavage fromthe resin takes place under the conditions used in embodiment b) of the process.

In accordance with embodiment c) of the process acidic compounds of formulaI can be converted into salts with bases, e.g. alkali metal salts such as sodium or potassium salts, alkaline earth metal salts such as calcium or magnesium salts, salts with organic bases, e.g. salts with amines such as N-ethylpiperidine, procaine or dibenzylamine, or salts with basic amino acids such as salts with arginine or lysine. The formation and isolation of such salts can be carried out according to conventional methods known in the art.

This invention provides acetal compounds of the formula ##STR12##wherein R¹ is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl,heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;

R² is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and

R³ is hydrogen or lower alkyl; or

R² and R³ together are di- or trimethylene optionally substitutedby hydroxy;

R⁴ is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, loweralkenyl, aryl or lower cycloalkyl;

R⁵ is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl;

R⁶ is hydrogen or lower alkyl;

R⁷ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl;

R⁸ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl;

R⁹ is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl; and

R¹⁰ and R¹¹ are each independently a lower alkyl. Preferred values of R¹ through R⁹ for compounds of formula II are as described above in connection with the compounds of formula I.

These acetal compounds can be prepared, for example, by firstly reducing a hydroxamate of the general formula ##STR13##wherein R¹, R¹⁰ and R¹¹ have the significance given earlier and

Q¹ represents an amino protecting group, e.g. tert.butoxy-carbonyl, with an alkali metal aluminium hydride, e.g. lithium aluminium hydride, treating the product with methanolic hydrochloric acid to give the hydrochloride salt of a compound of the formula ##STR14##wherein R¹, R¹⁰ and R¹¹ have the significance given earlier,and subsequently either subjecting this to sequential coupling with respective amino acids or subjecting a fragment obtained during such a sequential coupling to further coupling with a peptide derivative of appropriate length. Alternatively, a compound of formula V can be coupled with a suitable pentapeptide.

The aforementioned coupling reactions can be carried out in a manner known per se in peptide chemistry, conveniently using the respective amino acid or di, tri-, tetra- or pentapeptide appropriately protected as described above and also at any amino group present by Fmoc (9-fluorenyl)methoxycarbonyl! in the presence of hydroxybenzotriazole, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-methylmorpholine and in an inert organic solvent, e.g. a halogenated hydrocarbon such as dichloromethane.

The hydroxamates of formula IV required for the preparation of the acetal starting materials of formula II are known compounds or analogues of knowncompounds which can be prepared in an analogous manner to the known compounds.

The acetal starting materials of formula II can also be synthesised from a compound of formula V on a solid phase peptide synthesis resin. This procedure is known and is described in detail in Handbook from Fourth International Symposium on Solid Phase Synthesis and Combinatorial Chemical Libraries, Edinburgh, 1995.

This invention provides dioxaborolanes of formula ##STR15##wherein R¹ is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl,heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;

R² is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and

R³ is hydrogen or lower alkyl; or

R² and R³ together are di- or trimethylene optionally substitutedby hydroxy;

R⁴ is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, loweralkenyl, aryl or lower cycloalkyl;

R⁵ is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl;

R⁶ is hydrogen or lower alkyl;

R⁷ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl;

R⁸ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl; and

R⁹ is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl; and

Q is ##STR16##wherein R¹², R¹³, R¹⁴ and R¹⁵ each are hydrogen or lower alkyl and R¹⁶ and R¹⁷ each are hydrogen or lower alkyl, and wherein any carboxy, hydroxy or aminocarbonyl group present in the dioxoborolane is or is not protected. Prefered values of R¹ through R⁹ for the compounds of formula III are as described above for compounds of formula I. These dioxaborolanes, which include the substituted dioxaborolanes of formula III used as starting materials in embodiment b) of the process according to the invention can be prepared, for example, as illustrated in Scheme A hereinafter in which R¹ and Qhave the significance given earlier: ##STR17##

Having regard to Scheme A, in step a) a compound of formula VI is reacted with an alkali metal bis tri(lower alkyl)silyl!amide, e.g. lithium bis(trimethylsilyl)amide, in an inert organic solvent such as an ether, e.g. diethyl ether or tetrahydrofuran, and then treated with a strong acid, e.g. trifluoroacetic acid, to give a compound of formula VII.

In step b) a compound of formula VII is converted into a compound of formula III either by coupling with a pentapeptide, by sequential couplingwith respective amino acids or by coupling a fragment obtained during the sequential coupling with a peptide derivative of the desired length, with the amino acid or peptide used being appropriately protected as described above and also at any amino group present by Fmoc. These coupling reactions can be carried out in a manner known per se in peptide chemistry, for example using the amino acid or peptide in the form of a mixed anhydride formed e.g. with a lower alkyl haloformate such as isobutyl chloroformate and carrying out the coupling in the presence of a suitable base, e.g. a tertiary organic base such as N-methylmorpholine.

Substituted dioxoborolanes of formula III obtained by the foregoing coupling and which carry a protecting group on the substituent at R²,R⁴, R⁵, R⁷, R⁸ and/or R⁹ can be selectively deprotected in a conventional manner, e.g. using trifluoroacetic acid, to the corresponding compounds which carry a free carboxy, hydroxy and/or aminocarbonyl group on the respective substituent, while retaining the protected boronic acid moiety denoted by Q. These selectively deprotected compounds are also active as inhibitors of proteinases of viral origin andcan be used in the treatment of viral infections in the same manner as the compounds of formula I.

Compounds of formula VI can be prepared, for example, from a compound of the general formula

    Cl.sub.2 CH--Q                                             (VIII)

wherein Q has the significance given earlier, which is a known compound or an analogue of a known compound, by reaction with a compound of the formula R^(1a) --MgHal, wherein R^(1a) has the same significance as R¹ hereinbefore, but contains one carbon atom less and Hal representshalogen, preferably bromine. The reaction is carried out under the conventional conditions of a Grignard reaction, for example in an inert organic solvent such as an ether, e.g. diethyl ether or tetrahydrofuran. When Q represents a group of formula (b), the reaction is carried out in the presence of zinc chloride.

A compound of formula VI in which R¹ represents bromo-lower alkyl or fluoro-lower alkyl and Q represents a group of formula (a) can be prepared, for example, by hydroborating a bromo- or fluoro-lower alkene, e.g. 3-bromopropene or 3-fluoropropene, reacting the hydroboration productwith a diol of the formula R¹² R¹³ C(OH)--C(OH)R¹⁴ R¹⁵,wherein R¹², R¹³, R¹⁴ and R¹⁵ have the significance given earlier, e.g. 2,3-dimethyl-2,3-butanediol, and reacting the resulting 2-(bromo- or fluoro-lower alkyl)-1,3,2-dioxaborolane with dichloromethane in the presence of lithium diisopropylamine. The hydroboration can be carried out in a conventional manner, for example using phenylboronic acid at an elevated temperature, e.g. about 100° C., in the absence of a solvent or using borane-dimethyl sulphide complex in the presence of cyclohexene in an inert organic solvent, e.g. dimethoxyethane, at about 0° C. followed by treatmentwith trimethylamine N-oxide.

A substituted dioxoborolane of formula III in which Q represents a group offormula (a) can also be synthesised on a solid phase peptide synthesis resin. For example, a 4-methylbenzhydryl resin can be reacted with a dioxoborolanyl-valeric acid of the general formula ##STR18##wherein R¹, R², R¹², R¹⁴, R¹⁵ and Q¹ have thesignificance given earlier,

and the product can be converted into the required resin-bonded starting material by successive deprotection and coupling with a protected amino acid.

Compounds of formula IX can be conveniently prepared by reacting a tert-butyl 6,7-dihydroxy-3,6,7-tri(lower alkyl)-6-octenoate with dichloromethyl diisopropoxyborane, condensing the resulting compound of the general formula ##STR19##wherein R¹², ¹⁴ and R¹⁵ have the significance given earlier,with a compound of formula R¹ MgHal, wherein R¹ has the significance given earlier and Hal represents halogen, preferably bromine,under the conditions of a Grignard reaction, reacting the resulting compound of the general formula ##STR20##wherein R¹, R¹², R¹⁴ and R¹⁵ have the significance given earlier,

with an alkali metal bis tri(lower alkyl)silyl!amide, condensing the resulting compound of the general formula ##STR21##wherein R¹, R¹², R¹⁴ and R¹⁵ have the significance given earlier,

with a protected amino acid of the general formula

    Q.sup.2 HN--CH(R.sup.2)--COOH                              (XIII)

wherein R² has the significance given earlier and Q² represents Fmoc,

and de-esterifying the resulting compound of the general formula ##STR22##wherein R¹, R², R¹², R¹⁴, R¹⁵ and Q² have thesignificance given earlier.

As mentioned earlier, the compounds of formula I and salts of acidic compounds of formula I with bases are inhibitors of proteases of viral origin. The activity against one such protease, namly HCV protease, can bedemonstrated using the following assay:

Construction of plasmid for the expression of MBP-NS3"Gly 12-NS4A enzyme inE. coli

The nucleotide sequence of this expression plasmid is given in FIGS. 1a-j appended hereto and the amino acid sequence of its expression product is given in FIG. 2 appended hereto. It is based on the pMAL®-c2 vector supplied by New England Biolabs, Inc. (32 Tozer Rd., Beverly, Mass., USA).The principle of the construction was to create an in-frame fusion of the maltose binding protein (MBP) gene supplied by the pMAL-c2 vector, and sequences of the HCV genome necessary for NS3 proteinase activity. These HCV sequences were inserted between the EcoRI and HindIII sites of the pMAL-c2 polylinker (positions 2695 and 3556 respectively of the sequence given in FIGS. 1a-j).

HCV sequences were derived from plasmids pDS 3348-4045 and pBFK 3348-6062, described by Bartenschlager et al, 1993 (Journal of Virology, 67, 3835-3844). Regions encompassing the NS3 proteinase domain (amino acids 1007-1219) and the NS4A domain (amino acids 1658-1711) were isolated and inserted into the pMAL-c2 vector using standard recombinant DNA techniques, including the PCR amplification of required sequences. Betweenthe NS3 and NS4A domains, a linker region was constructed using synthetic oligonucleotides (positions 3343-3390; amino acids 606-621). The resultingplasmid was used to transform E. coli (strain MC1061) cells and expression of the MBP-NS3"Gly₁₂ -NS4A enzyme was induced as described below.

Protein expression and purification

E. coli (strain MC1061) cells transformed with the foregoing plasmid were grown in Luria broth containing ampicillin (100 μg/ml) at 37° C.The cells were grown until an optical density of 0.5 at 600 nm had been reached and enzyme expression was then induced by adding 1 mM isopropylthiogalactoside and incubating at 37° C. for a further 3 hours. The cells were harvested by centrifugation and stored at -80° C.

A pellet from 4 l of bacterial culture was resuspended in E.coli lysis buffer (20 mM Tris HCl, pH 7.5, containing 150 mM NaCl, 1 mM EDTA and 10 mM dithiothreitol) and cell lysis was achieved by two passages through a French Pressure cell. The clear supernatant obtained by centrifugation (18000 g, 30 minutes) was then applied to an amylose resin column (4×1 cm) (New England Biolabs) which had been equilibrated with ice-cold 50 mM Tris HCl, pH 8.5, containing 200 mM NaCl, 1 mM dithiothreitol and 5% glycerol. The column was washed thoroughly with the equilibration buffer and bound protein was eluted using the equilibration buffer containing 10 mM maltose. Fractions of 1 ml were collected, with fractions containing the enzyme being pooled and stored at -80° C. Enzyme concentration was assayed by the method of M. B. Bradford, Analytical Biochemistry, 1976, vol. 72, p.248.

Assay

Compounds of formula I (routinely prepared as stock solutions in DMSO) wereassayed for their ability to inhibit the cleavage of a quenched fluorescence substrate NS4A/B.F peptide (N- 4- 4-(dimethylamino)phenylazo!benzoyl!-L-α-aspartyl-L-α-glutamyl-L-methionyl-L-(x-glutamyl-L-α-glutamyl-L-cysteinyl-L-alanyl-L-seryl-L-histidyl-N5- 2-(5-sulpho-1-naphthylamino)ethyl!-L-glutaminamide); Wilkinson et al, Society for General Microbiology Meeting, University of Warwick, England, 28 Mar. 1996! based on the NS4A/4B cleavage site by enzyme MBP-NS3"Gly₁₂ -NS4A in microtitre plates as follows:

The enzyme (1 μg) was added to 200 μl final volume of a mixture containing 50 mM Tris HCl, pH 8.5, with 1 mM dithiothreitol, 0.1% Triton X-100 and the test compound of formula I. The resulting mixture was incubated at room temperature for 15 minutes prior to starting the reaction by the addition of NS4A/B.F peptide to a final concentration of 10 μM. The progress of the reaction was evaluated with a Perseptive Biosystems Cytofluor II using an excitation wavelenth of 360 nm and an emission wavelength of 530 nm. After incubation for a further 10 minutes, the reduction in fluorescence in the presence of inhibitor was measured. This was plotted against inhibitor concentration and the inhibitor concentration which caused 50% reduction (IC₅₀) was calculated by manual graphical analysis or by the use of the Perseptive Biosystems Cytocalc curve fitting program.

The results obtained in the foregoing assay with representative compounds of formula I are compiled in the following Table:

                  TABLE     ______________________________________     Compound of formula I                    HCV proteinase IC.sub.50 (μmol/l)     ______________________________________     A              0.09     B              0.07     C              0.064     D              0.034     E              0.038     F              0.16     ______________________________________

Compounds:

A=2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-pentenaldehyde.

B=2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4-difluorovaleraldehyde.

C=2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde.

D=1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-butenylboronic acid.

E=1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!propylboronic acid.

F=1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!butylboronic acid.

The compounds of formula I and salts of acidic compounds of formula I with bases can be used as medicaments, e.g. in the form of pharmaceutical preparations. The pharmaceutical preparations can be administered enterally such as orally in the form of tablets, coated tablets, drag6s, hard and soft gelatine capsules, solutions, emulsions or suspensions, nasally, e.g. in the form of nasal sprays, or rectally, e.g. in the form of suppositories. They may, however, also be administered parenterally, e.g. in the form of injection solutions. In one embodiment, this inventionprovides a pharmaceutical composition comprising from ten to five hundred milligrams of a compound of each of the embodiments of compounds of formula I described above, and a compatible pharmaceutical carrier.

The compounds of formula I and their aforementioned salts can be processed with pharmaceutically inert, organic or inorganic carriers for the production of pharmaceutical preparations. Lactose, corn starch or derivatives thereof, talc, stearic acid or its salts and the like can be used, for example, as such carriers for tablets, coated tablets, dragees and hard gelatine capsules. Suitable carriers for soft gelatine capsules are, for example, vegetable oils, waxes, fats, semi-solid and liquid polyols and the like; depending on the nature of the active ingredient no carriers are, however, usually required in the case of soft gelatine capsules. Suitable carriers for the production of solutions and syrups are, for example, water, polyols, sucrose, invert sugar, glucose and the like. Suitable carriers for suppositories are, for example, natural or hardened oils, waxes, fats, semi-liquid or liquid polyols and the like.

The pharmaceutical preparations can also contain preservatives, solubilizers, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, flavorants, salts for varying the osmotic pressure, buffers, masking agents or antioxidants. They can also contain still other therapeutically valuable substances.

Medicaments containing a compound of formula I or a salt of an acidic compound of formula I with a base in association with a compatible pharmaceutical carrier are also an object of the present invention, as is a process for the production of such medicaments which comprises bringing one or more of these compounds or salts and, if desired, one or more othertherapeutically valuable substances into a galenical administration form together with a compatible pharmaceutical carrier.

As mentioned earlier, the compounds of formula I and salts of acidic compounds of formula I with bases can be used in accordance with the invention as therapeutically active substances, especially as antiviral agents. The dosage can vary within wide limits and will, of course, be fitted to the individual requirements in each particular case. In general,in the case of administration to adults a convenient daily dosage should beabout 3 mg to about 3 g, preferably about 10 mg to 1 g. The daily dosage may be administered as a single dose or in divided doses and, in addition,the upper dosage limit referred to earlier may be exceeded when this is found to be indicated.

Finally, the use of compounds of formula I and salts of acidic compounds offormula I with bases for the production of medicaments, especially of antiviral medicaments, is also an object of the invention.

The invention is illustrated by the following Examples. In the Examples SSAdenotes the solvent system 0.1% TFA in water and SSB denotes the solvent system 0.1% TFA in 70% acetonitrile 30% water.

EXAMPLE 1

0.1 g (0.1 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)-propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)propyl!-L-leucinamide was dissolved in3 ml of dichloromethane, 3 ml of trifluoroacetic acid and 90 mg of water and the mixture was stirred at room temperature for 30 minutes. The solution was diluted with 20 ml of toluene and the solvent was removed by evaporation. The resulting white solid was triturated with diethyl ether and filtered off. The solid was purified by RP-HPLC on a C18 Dynamax column (pore size 300 Å; column size 21.4 mm×50 mm). The elutiongradient comprised 90% SSA 10% SSB to 95% SSB 5% SSA over 8.5 minutes. After lyophilization overnight there were obtained 25 mg of 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!butyraldehyde as a white foam. MS: m/e 819.5 M+H!⁺.

The starting material was prepared as follows:

i) A solution of 25 g (63.6 mmol) of L-leucine benzyl ester p-toluenesulphonic acid salt, 14.69 g (63.6 mmol) of N-(tert-butoxycarbonyl)-3-methyl-L-valine, 9.73 g (63.6 mmol) of 1-hydroxybenzotriazole, 7.32 g (63.3 mmol) of N-ethylmorpholine and 12.21 g (63.6 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 500 ml of dichloromethane was stirred at room temperatureovernight. The solution was washed with water, sodium hydrogen carbonate solution, 2M hydrochloric acid and saturated sodium chloride solution and dried over anhydrous magnesium sulphate. Evaporation gave 21.65 g of N- (N-tert-butoxycarbonyl)-3-methyl-L-valyl!-L-leucine benzyl ester as an oil which was used in the next step without further purification. MS: m/e 435 M+H!⁺.

ii) A solution of 9.74 g (22.4 mmol) of N- (N-tert-butoxycarbonyl)-3-methyl-L-valyl!-L-leucine benzyl ester in 25 ml of trifluoroacetic acid and 50 ml of dichloromethane was stirred at room temperature for 30 minutes. The solvent was removed by evaporation and 50 ml of toluene were added. Evaporation gave N-(3-methyl-L-valyl)-L-leucine benzyl ester as an oil which was used in the next step without further purification.

iii) A solution of the foregoing oil, 9 g (22.4 mmol) of N-(9-fluorenylmethoxycarbonyl)-2-methyl-L-phenylalanine, 3.43 g (22.4 mmol) of 1-hydroxybenzotriazole, 3.87 g (33.66 mmol) of N-ethylmorpholine and 4.31 g (22.4 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 100 ml of dichloromethane was stirred at room temperatureovernight. The solution was washed with water, sodium hydrogen carbonate solution, 2M hydrochloric acid and saturated sodium chloride solution and dried over anhydrous magnesium sulphate. Evaporation and chromatography onsilica gel using 30% ethyl acetate in petroleum ether (b.p. 40°-60° C.) for the elution gave 12.32 g of N- N- N- (9-fluorenyl)methoxycarbonyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester as an oil. MS: m/e 718 M+H!⁺.

iv) A solution of 10 g (13.95 mmol) of N- N- N- (9-fluorenyl)-methoxycarbonyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester in 30 ml of piperidine and 120 ml of dichloromethane was stirred for 30 minutes at room temperature. The solvent was removed by evaporation and the residue was chromatographed on silica gel using firstly 20% ethyl acetate in hexane and then 10% methanolin dichloromethane for the elution. Evaporation gave 6.9 g of N- N- 2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester inthe form of an oil which was used in the next step without further purification.

v) A solution of 6.9 g of the foregoing oil, 2.13 g (13.95 mmol) of 1-hydroxybenzotriazole, 2.68 g (13.95 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 5.93 g (13.95 mmol) of N- (9-fluorenyl)methoxycarbonyl!-O-tert.-butyl-L-α-glutamic acid in 150 ml of dichloromethane was stirred at room temperature overnight. The solution was washed with water, sodium hydrogen carbonate solution, 2M hydrochloric acid and saturated sodium chloride solution and dried over anhydrous magnesium sulphate. Evaporation and chromatography of the residue on silica gel using 30% ethyl acetate in petroleum ether (b.p. 40°-60° C.) for the elution gave 10.89 g of N- N- N- N- (9-fluorenyl)-methoxycarbonyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester as a thick oil. MS: m/e 903 M+H!⁺.

vi) A solution of 10.89 g (12.07 mmol) of N- N- N- N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester in 30 mlof piperidine and 120 ml of dichloromethane was stirred for 30 minutes at room temperature. The solvent was removed by evaporation and the residue was chromatographed on silica gel using firstly 20% ethyl acetate in hexane and then 10% methanol in dichloromethane for the elution. Evaporation gave N- N- N- O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester in the form of an oil which was used in the next step without further purification.

vii) A solution of the foregoing oil, 4.96 g (12.07 mmol) of N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-aspartic acid, 1.85 g (12.07 mmol) of 1-hydroxybenzotriazole and 2.32 g (12.07 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 100 ml of dichloromethane was stirred at room temperature overnight. The solution was washed with water, sodium hydrogen carbonate solution, 2M hydrochloricacid and saturated sodium chloride solution and dried over anhydrous magnesium sulphate. Evaporation and chromatography of the residue on silica gel using ethyl acetate for the elution gave 10.088 g of N- N- N- N- N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester as a white solid. MS: m/e 1074 M+H!⁺.

viii) A solution of 10.088 g (9.4 mmol) of N- N- N- N- N- (9-fluorenyl)methoxycarbonyl! O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester in 30 ml of piperidine and 120 ml of dichloromethane was stirred for 30 minutes at room temperature. The solvent was removed by evaporation and the residue was chromatographed on silica gel using firstly 20% ethyl acetate in hexane and then 10% methanol in dichloromethane for the elution. Evaporation gave N- N- N- N- O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl-2-methyl-L-phenylalanyl!-3-methyl-L-valyl-L-leucine benzyl ester in the form of an oil which was used in the next step without further purification.

ix) A solution of 8 g of the foregoing oil, 1.64 g (9.4 mmol) of tert-butylhydrogen succinate, 1.44 g (9.4 mmol) of 1-hydroxybenzotriazole and 1.805 g(9.4 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in dichloromethane was stirred at room temperature overnight. The solutionwas washed with water, sodium hydrogen carbonate solution, 2M hydrochloric acid and saturated sodium chloride solution and dried over anhydrous magnesium sulphate. Evaporation and trituration of the residue with acetone gave 6.87 g of N- N- N- N-- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester as a white solid. MS: m/e 1008.6 M+H!⁺, m/e 1030.3 M+Na!⁺.

x) A solution of 6.8 g (6.75 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester in 200 ml of dimethylformamide was hydrogenated over 600 mg of 10% palladium/carbon for 1 hour. The catalyst was removed by filtration and the filtrate was evaporated to give 15 g of crude product which was chromatographed on silica gel using 10-15% methanol in dichloromethane for the elution to give 6 g of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine as a white solid of melting point 235°-236° C.; MS: m/e 918.4 M+H!⁺, m/e 940.3 M+Na!⁺.

xi) 370 mg (2.5 mmol) of N,O-dimethyl 2(S)-(tert-butoxyformamido)butyrohydroxamate were dissolved in 20 ml of anhydrous tetrahydrofuran under nitrogen and the solution was cooled to 0° C. in an ice-bath. 1.5 ml (1.5 mmol) of 1M lithium aluminium hydride in tetrahydrofuran were added and the mixture was stirred at 0° C. for minutes. 20 ml of saturated aqueous potassium hydrogen sulphate were added and the mixture was stirred vigorously under nitrogen for 30 minutes at room temperature. The mixture was then diluted with 50 ml of diethyl ether and the organic layer was separated, dried over anhydrous magnesium sulphate and the solvent was evaporated. The residue was dissolved in 10 ml of a saturated methanolic hydrogen chloride solution, stirred for 1 hour, then diluted with 50 ml of toluene and evaporated to dryness. The resulting oil was dissolved in 10 ml of dichloromethane and 184 mg (0.2 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl) propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine, 58 mg (0.3 mmol) of 2-(3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride, 41 mg (0.3 mmol) of 1-hydroxy-7-azabenzotriazole and 350 mg (3.0 mmol) of N-ethylmorpholine were added. The mixture was stirred for 30 minutes then washed in sequence with saturated sodium bicarbonate solution and 2M hydrochloric acid and dried over anhydrous magnesium sulphate. The solution was evaporated to dryness and the residue was chromatographed on silica gel using 4% methanol in dichloromethane for the elution. After trituration with diethyl ether there were obtained 110 mg of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)propyl!-leucinamide as a white solid ofmelting point 242°-244° C. MS: m/e 1001.5 M+H-MeOH!⁺, m/e 1055 M+Na!⁺.

Analysis for C₅₃ H₈₈ O₁₄ N₆ 1033.315!. Calculated: C, 61.61; H, 8.58; N, 8.13% Found: C, 61.52, H, 8.45; N, 8.19%

EXAMPLE 2

70 mg (0.067 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-L-leucinamide were stirred in a mixture of 4 ml of trifluoroacetic acid, 4 ml of dichloromethane and 30 mg of water at room temperature for 30 minutes. The solution was evaporated to dryness in a vacuum and the residue was chromatographed on silica gel using dichloromethane/methanol/acetic acid/water (60:13:2:2) for the elution. There were obtained 36 mg of 2(RS)- N- N- N- N- N- (3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-pentynal (9:1 mixture of diastereoisomers) as a white solid. MS: m/e 829.6 M+H!⁺.

The starting material was prepared as follows:

i) A solution of 12.17 g (57.14 mmol) of N-(tert-butoxycarbonyl)-1(S)-amino-4-pentynoic acid, 8.74 g (64.74 mmol) of hydroxybenzotriazole, 6.96 g (71.43 mmol) of N,O-dimethylhydroxylamine,8.21 g (71.43 mmol) of N-ethylmorpholine and 13.7 g (71.43 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 250 ml of dichloromethane was stirred for 18 hours, then washed with 2M hydrochloricacid and saturated sodium bicarbonate solution, dried and evaporated to give 14.2 g of N,O-dimethyl 2(S)-(tert-butoxyformamido)-4-pentynohydroxamate as a viscous gum which slowly crystallized.

Analysis for C₁₂ H₂₀ N₂ O₄ 256.302!. Calculated: C, 56.24; H, 7.87; N, 10.93% Found: C, 56.01, H, 7.81; N, 10.92%

ii) 10 ml (10 mmol) of 1M lithium aluminium hydride in tetrahydrofuran wereadded to a solution of 3.15g (12.3mmol) of N,O-dimethyl 2(S)-(tert-butoxyformamido)-4-pentynohydroxamate in 50 ml of dry tetrahydrofuran at 0° C. under a nitrogen atmosphere. The solution was stirred for 20 minutes and then 40 ml of saturated potassium hydrogen sulphate solution were added dropwise. The mixture was stirred for 15 minutes and then diluted with diethyl ether. The organic layer was dried over magnesium sulphate and evaporated to give an oil which was dissolved in 50 ml of methanolic hydrogen chloride solution. The solution was left at room temperature for 1 hour and then evaporated to dryness to give a dark brown gum. 1.05 g of the gum were added to a solution of 2.06 g (5.84mmol) of N- (9-fluorenyl)methoxycarbonyl!-L-leucine, 867 mg (6.42 mmol) of hydroxybenzotriazole, 1.233 g (6.42 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 2.216 g (19.27 mmol) of N-ethylmorpholine in 40 ml of dichloromethane. The solution was stirred at room temperature for 18 hours, washed with 2M hydrochloric acid and saturated sodium bicarbonate solution, dried over magnesium sulphate and evaporated to give a gum which was chromatographed on silica gel using ethyl acetate/petrol (2:3) for the elution. There wereobtained 1.1 g of N2- (9-fluorenyl)methoxycarbonyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-L-leucinamide as an off-white solid. ¹ H NMR (400 MHz, DMSO-d₆) δ: 0.86 (6 H,dd), 1.35-1.65 (3 H,m), 2.22-2.39 (2 H,m), 2.75(1 H,t),3.22 (3 H,s), 3.27 (3 H,s), 3.91 (1 H,m), 4.08 (1 H,m), 4.15-4.3 (4 H,m), 7.29 (2 H,m), 7.4 (2 H,t), 7.42 (1 H,d), 7.71 (2 H,d), 7.84 25 (1 H,d), 7.88 (2 H,d).

iii) 525 mg (1.1 mmol) of N2- (9-fluorenyl)methoxycarbonyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-L-leucinamide were dissolved in 20 ml of dichloromethane and 5 ml of piperidine and the mixture was stirred at room temperature for 30 minutes.The mixture was evaporated to dryness and the residue was chromatographed on silica gel using firstly ethyl acetate/petrol (1:1) and then methanol/dichloromethane (1:9) for the elution. Evaporation of the dichloromethane solution gave a gum which was added to a solution of 363 mg (1.03 mmol) of N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-leucine, 149mg (1.1 mmol) of hydroxybenzotriazole and 288 mg (1.5 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 15 ml of dichloromethane. The mixture was stirred for 18 hours, then washed with 2Mhydrochloric acid and saturated sodium bicarbonate solution, dried over magnesium sulphate and evaporated to dryness. The residue was chromatographed on silica gel using ethyl acetate/petrol (1:2) for the elution to give 501 mg of N2- N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-L-leucinamide as a white foam. MS: m/e 592.3 M+H!⁺, 560.3 M+H-MeOH!⁺.

iv) 490 mg (0.83 mmol) of N2- N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-L-leucinamide were dissolved in 16 ml of dichloromethaneand 4 ml of piperidine and the mixture was stirred at room temperature for 30 minutes. The mixture was evaporated to dryness and the residue was chromatographed on silica gel using firstly ethyl acetate/petrol (1:1) andthen methanol/dichloromethane (1:9) for the elution. Evaporation of the dichloromethane solution gave a gum which was added to a solution of 321 mg (0.8 mmol) of N- (9-fluorenyl)methoxycarbonyl!-2-methyl-L-phenylalanine, 122 mg (0.9 mmol) of hydroxybenzotriazole and 192 mg (1 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 15 ml of dichloromethane. The mixture was stirred for 18 hours, then washed with 2Mhydrochloric acid and saturated sodium bicarbonate solution, dried over magnesium sulphate and evaporated to dryness. The residue was chromatographed on silica gel using ethyl acetate/petrol (2:3) for the elution to give a white foam which was dissolved in 16 ml of dichloromethane and 4 ml of piperidine and left at room temperature for 30minutes. The mixture was evaporated to dryness and the residue was chromatographed on silica gel using firstly ethyl acetate/petrol (1:1) andthen methanol/dichloromethane (1:9) for the elution. Evaporation of the dichloromethane solution gave a gum which was added to a solution of 213 mg (0.5 mmol) of N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-glutamic acid, 74 mg (0.55 mmol) of hydroxybenzotriazole and 115 mg (0.6 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 10 ml of dichloromethane. The mixture was stirred for 18 hours, then washed with 2Mhydrochloric acid and saturated sodium bicarbonate, dried over magnesium sulphate and evaporated to dryness. Trituration of the residue with diethyl ether gave 345 mg of N2- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-leucinamide as a white solid. MS: m/e 938 M+H!⁺, 906 M+H-MeOH!⁺.

v) 340 mg (0.36 mmol) of N2- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-glutamyl!-2-methyl-L-phenyl-alanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-L-leucinamide were dissolved in 12 ml of dichloromethane and 3 ml of piperidine and the mixture was stirred at room temperature for 30 minutes. The mixture was evaporated to dryness and the residue was chromatographed on silica gel using firstly ethyl acetate/petrol (1:1) andthen methanol/ dichloromethane (1:9) for the elution. Evaporation of the dichloromethane solution gave a gum which was added to a solution of 144 mg (0.35 mmol) of N- (9-fluorenyl) methoxycarbonyl!-O-tert-butyl-L-α-aspartic acid, 54 mg (0.4 mmol) ofhydroxybenzotriazole and 96 mg (0.5 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 15 ml of dichloromethane. The mixture was stirred for 18 hours, then washed with 2Mhydrochloric acid and saturated sodium bicarbonate solution, dried over magnesium sulphate and evaporated to dryness. Trituration of the residue with diethyl ether gave 360 mg of N2- N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-L-leucinamide as a white solid.MS: m/e 1077 M+H-MeOH!⁺.

vi) 350 mg (0.32 mmol) of N2- N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-L-leucinamide were dissolved in12 ml of dichloromethane and 3 ml of piperidine and the mixture was stirredat room temperature for 30 minutes. The mixture was evaporated to dryness and the residue was chromatographed on silica gel using firstly ethyl acetate/petrol (1:1) and then methanol/dichloromethane (1:9) for the elution. Evaporation of the dichloromethane solution gave a foam which wasadded to a solution of 104 mg (0.6 mmol) of succinic acid monotert-butyl ester, 81 mg (0.6 mmol) of hydroxybenzotriazole and 192 mg (1 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 10 ml of dichloromethane. The mixture was stirred for 18 hours, then washed with 2Mhydrochloric acid and saturated sodium bicarbonate solution, dried over magnesium sulphate and evaporated to dryness. Chromatography of the residue on silica gel using 4% methanol in dichloromethane for the elutionand trituration with ethyl acetate gave 145 mg of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-butynyl!-L-leucinamide as a white solid. MS: m/e 1043 M+H!⁺, 1011 M+H-MeOH!⁺.

EXAMPLE 3

94 mg (0.86 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)-propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 3,3,3-trifluoro-1(S)-(dimethoxymethyl)propyl!-L-leucinamide were stirred in a mixture of 4 ml of trifluoroacetic acid, 4 ml of dichloromethane and 30 mg of water at room temperature for 30 minutes. Thesolution was evaporated to dryness in a vacuum and the residue was chromatographed on silica gel using dichloromethane/methanol/acetic acid/water (120:15:3:2) for the elution. There were obtained 41 mg of 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde (7:1 mixture of diastereoisomers) as a white solid. MS: m/e 873 M+H!⁺.

The starting material was prepared as follows:

184 mg (0.2 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine were suspended in 6 ml of dichloromethane and treated with 34 mg (0.25 mmol) of hydroxybenzotriazole followed by 391 mg (1.75 mmol) of 3,3,3-trifluoro-1(S)-dimethoxymethyl-propylamine hydrochloride and 690 mg (6 mmol) of N-ethylmorpholine. The mixture was stirred for 2 hours, then washed in sequence with 2M hydrochloric acid and saturated sodium bicarbonate solution and dried over magnesium sulphate. The solventwas removed by evaporation and the resulting solid, after trituration with diethyl ether, was chromatographed on silica gel using 4% methanol in dichloromethane for the elution. There were obtained 101 mg of N2- N- N- N- N- (3-tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 3,3,3-trifluoro-1(S)-(dimethoxymethyl)propyl!-L-leucinamide as a white solid. MS: m/e 1088 M+H!⁺.

EXAMPLE 4

0.02 g (0.006 mmol) of 5- 4- N- N- N- (9-fluorenyl)-methoxycarbonyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!-N-3,3,3-trifluoro-1(RS)-(dimethoxymethyl)propyl!-amino!methyl!-3,5-dimethoxyphenoxy!-N-(4-methyl-α-(RS)-phenylbenzyl)valeramide-polystyrene conjugate was suspended and agitated in 0.7 ml of dimethylformamide/piperidine (4:1). After 5 minutes the resin was drained and then resuspended in and agitated with 0.7 ml of dimethylformamide/piperidine (4:1) for a further 5 minutes. The resin was then drained and washed five times with 1.5 ml of dimethylformamide.

The resin was then suspended in a solution of 0.026 g (0.06 mmol) of N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine in 0.3 ml of dimethylformamide and then a mixture of 0.019 g (0.06 mmol) of 2-(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoraborate and 0.012 g (0.12 mmol) of N-methylmorpholine dissolved in 0.3 ml of dimethylformamide was added. After agitating for 2 hours the resin was drained and washed five times with 1.5 ml of dimethylformamide.

The resin was resuspended in and agitated with 1.5 ml of dimethylformamide/piperidine (4:1). After 5 minutes the resin was drained and resuspended in and agitated with dimethylformamide/piperidine(4:1) fora further 5 minutes. Then, the resin was drained and washed five times with1.5 ml of dimethylformamide.

The resin was then suspended in a solution of 0.025 g (0.06 mmol) of N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-aspartic acid in 0.3 ml of dimethylformamide and then a mixture of 0.019 g (0.06 mmol) of 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoraborate and 0.012 g (0.12 mmol) of N-methylmorpholine dissolved in 0.3 ml of dimethylformamide was added. After agitating for 2 hours the resin was drained and washed five times with 1.5 ml of dimethylformamide.

The resin was resuspended in and agitated with 1.5 ml of dimethylformamide/piperidine (4:1). After 5 minutes the resin was drained and resuspended in and agitated with dimethylformamide/piperidine (4:1) for a further 5 minutes. Then, the resin was drained and washed five timeswith 1.5 ml of dimethylformamide.

The resin was then suspended in a solution of 0.01 g (0.06 mmol) tert-butylhydrogen succinate in 0.3 ml of dimethylformamide and treated with a mixture of 0.019 g (0.06 mmol) 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 0.012 g (0.12 mmol) of N-methylmorpholine dissolved in 0.3 ml of dimethylformamide. After agitating for 2 hours the resin was drained and washed 5 times with 1.5 ml of dimethylformamide and then twice with 1.5 mlof dichloromethane.

The resin was treated with 0.8 ml of trifluoroacetic acid/water (19:1) and then agitated for 30 minutes. It was then filtered off and washed with 0.8ml of trifluoroacetic acid/ water (19:1). The combined trifluoroacetic acid/water mixtures were then evaporated in a vacuum centrifuge and the residue was suspended in 0.8 ml of acetonitrile/water (1:1) and freeze dried. There were obtained 6.3 mg of 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-3-(2-naphthyl)-D-alanyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 941.5 M+H!⁺.

The starting material was prepared as follows:

i) 18 g (60.0 mmol) of N,O-dimethyl 2(RS)-(tert-butoxyformamido)-4,4,4-trifluorobutyrohydroxamate were dissolved in 230 ml of anhydrous tetrahydrofuran and the solution was cooled to 0° C. 48 ml (48 mmol) of a 1M solution of lithium aluminium hydride in tetrahydrofuran were then added dropwise while maintaining the temperature at 0° C. The mixture was stirred for 10minutes at 0° C. and then the reaction was quenched by the dropwise addition of saturated potassium hydrogen sulphate solution to pH 1 while maintaining the temperature at below 20° C. The resulting white slurry was stirred vigorously for a further 30 minutes and was then partitioned in three equal aliquots of diethyl ether. The combined diethylether fractions were washed with saturated sodium chloride solution, dried over anhydrous magnesium sulphate, filtered and evaporated. The residue was then dissolved in 100 ml of anhydrous saturated methanolic hydrogen chloride solution and left overnight at 4° C. The mixture was evaporated and the residue was triturated with dichloromethane. The filtrate was evaporated and the residue was chromatographed on silica gel using 5% methanol, 3% acetic acid and 1.5% water in dichloromethane for the elution. There were obtained 8.80 g of 3,3,3-trifluoro-2(RS)-(dimethoxymethyl)-propylamine hydrochloride as a white solid. ¹ H NMR : (CDCl₃) δ: 2.60-2.96 (m,2 H), 3.49 (d,6 H), 3.57-3.69 (q,1 H), 4.66 (d,1 H), 8.72 (br s,3 H).

ii) To a stirred mixture of 5.6 g (25.0 mmol) of 3,3,3-trifluoro-2(RS)-(dimethoxymethyl)-propylamine hydrochloride 3.65 ml of triethylamine, 7.8 g (25.0 mmol) of 4- 4-(ethoxycarbonyl)butoxy!2,6-dimethoxybenzaldehyde and 25 g of 3 Å molecular sieves in dichloromethane were added 5.8 g (27.5 mmol) of sodiumtriacetoxyborohydride. After 3 hours the molecular sieves were removed by filtration. The filtrate was then washed with three equal aliquots of saturated sodium bicarbonate solution and dried over anhydrous magnesium sulphate and filtered. The solvent was removed by evaporation and the resulting orange oil was chromatographed on silica gel using 60% ethyl acetate in hexane for the elution. There were obtained 10.4 g of ethyl 5- 4- 3,3,3-trifluoro-1(RS)-(dimethoxymethyl)propylamino!methyl!-3,5-dimethoxyphenoxy!valerate as a pale orange oil; ¹ H NMR : (CDCl₃)δ: 1.25 (t,3 H), 1.78-1.87 (m,4 H), 2.18-2.52 (m,4 H), 2.86-2.92 (m,1 H), 3.33 (d,6 H), 3.77 (s,6 H), 3.81 (d,2 H), 3.96 (t,2 H),4.13 (q,2 H), 4.26 (d,1 H), 6.18 (s,2 H); MS: m/e 482.2 M+H!, 504.2 M+Na!.

iii) A solution of 6.6 g (18.7 mmol) of N- (9-fluorenyl)-methoxycarbonyl!-L-leucine and 9.7 g (18.7 mmol) of 7-azabenzotriazol-1-yloxytris(pyrrolidino)phosphonium hexafluorophosphate in 50 ml of anhydrous dichloromethane was stirred at room temperature for 15 minutes. To this mixture were then added 6.0 g (12.4 mmol) of ethyl 5- 4- 3,3,3-trifluoro-1(RS)-(dimethoxymethyl)propylamino!methyl!-3,5-dimethoxyphenoxy!valerate and 4.3 ml of (24.8 mmol) diisopropylethylamine. After stirring overnight at 250C the mixture was diluted with dichloromethane and washed in sequence with water, 10% citric acid solution, saturated sodium hydrogen carbonate solution and saturated sodium chloride solution, then dried over anhydrous magnesium sulphate andfiltered. The solvent was removed by evaporation and the residue was chromatographed on silica gel using 30% ethyl acetate in hexane for the elution. There were obtained 8.06 g of ethyl 5- 4- N- N- (9-fluorenyl)methoxycarbonyl!-L-leucyl!-N- 3,3,3-trifluoro-1(RS)-(dimethoxymethyl)propyl!amino!methyl!-3,5-dimethoxyphenoxy!valerate; MS: m/e 839.4 M+Na!, 855.3 M+K!.

iv) 8.0 g (9.8 mmol) of 5- 4- N- N- (9-fluorenyl)methoxycarbonyl!-L-leucyl!-N- 3,3,3-trifluoro-1(RS)-(dimethoxymethyl)-propyl!amino!methyl!-3,5-dimethoxyphenoxy!valerate and 40 ml of piperidine were dissolved in 145 ml of dry dichloromethane and the solution was stirred at room temperature for 30 minutes. It was then evaporated in a vacuum and the residue was chromatographed on silica gel using 2% methanol, 49% dichloromethane and 49% hexane followed by 5% methanol, 47.5% dichloromethane and 47.5% hexane for the elution. There were obtained 4.09 g of ethyl 5- 4- N- 3,3,3-trifluoro-1(RS)-dimethoxymethyl)propyl!-N-(L-leucyl)amino!-methyl!-3,5-dimethoxyphenoxy!valerate as a clear stiff oil; MS: m/e 595 M+H!.

v) A solution of 2.76 g (7.8 mmol) of N- (9-fluorenyl)-methoxycarbonyl!-3-methyl-L-valine, 1.60 g (8.5 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1.60 g (10.7 mmol) of N-hydroxybenzotriazole in 70 ml of dichloromethane was stirred at 0° C. for 15 minutes. There were then added 4.06 g (7.1 mmol) of ethyl 5- 4- N- 3,3,3-trifluoro-1(RS)-(dimethoxymethyl)propyl!-N-(L-leucyl)-amino!methyl!-3,5-dimethoxyphenoxy!valerate and 2.7 ml (21.3 mmol) of N-ethylmorpholine in 70 ml of dichloromethane. After stirring overnight atroom temperature the mixture was washed in sequence with 10% citric acid solution, saturated sodium hydrogen carbonate solution and saturated sodium chloride solution, dried over anhydrous magnesium sulphate, filtered and evaporated. The residue was chromatographed on silica gel using 35% ethyl acetate in hexane for the elution. There were obtained 6.11 g of ethyl 5- 4- N- N- N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-valyl!-L-leucyl!-N- 3,3,3-trifluoro-1(RS)-(dimethoxyethyl)propyl!amino!methyl!-3,5-dimethoxy-phenoxy!valerate as a white foam; MS: m/e 952.5 M+Na!, 968.5 M+K!.

vi) 5.8 g (6.3 mmol) of ethyl 5- 4- N- N- N- (9-fluorenyl)-methoxycarbonyl!-3-methyl-L-valyl!-L-leucyl!-N- 3,3,3-trifluoro-1(RS)-(dimethoxyethyl)propyl!amino!methyl!-3,5-dimethoxyphenoxy!valerate and 18 ml of piperidine were dissolved in 90 ml of dichloromethane and the solution was stirred at room temperature for 1 hour. It was then evaporated and the residue was chromatographed on silicagel using 3% methanol, 48.5% dichloromethane and 48.5% hexane for the elution. There were obtained 4.1 g of ethyl 5- 4- N- 3,3,3-trifluoro-1(RS)-(dimethoxymethyl)propyl!-N- N-(3-methyl-L-valyl)-L-leucyl!amino!methyl!-3,5-dimethoxyphenoxy!-valerate as a white foam; MS: m/e 708.6 M+H!, 730.5 M+Na!.

vii) 4.0 g (5.7 mmol) of ethyl 5- 4- N- 3,3,3-trifluoro-1(RS)-(dimethoxymethyl)propyl!-N- N-(3-methyl-L-valyl)-L-leucyl-amino!methyl!-3,5-dimethoxyphenoxy!-valerate were dissolvedin 40 ml of methanol. 2.4 g (17.3 mmol) of potassium carbonate and 8.0 ml of water were then added and the mixture was stirred for 2 days at room temperature. The solvent was removed by evaporation and the residue was dissolved in 20 ml of water and 20 ml of dioxan. 2.9 g (8.6 mmol) of N- (9-fluorenyl)-methoxycarbonyloxy!-succinimide were then added and the mixture was stirred for 3 hours. The mixture was adjusted to pH 3 with 10%citric acid and then washed with three equal aliquots of dichloromethane. The combined organic layers were washed with saturated sodium chloride solution, dried over anhydrous magnesium sulphate, filtered and the filtrate was evaporated. The residue was chromatographed on silica gel using 4% tert-butyl methyl ether in dichloromethane for the elution. Therewere obtained 5.12 g of 5- 4- N- N- N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-valyl!-L-leucyl!-N- 3,3,3-trifluoro-1(RS)-(dimethoxymethyl)propyl!amino!methyl!-3,5-dimethoxyphenoxy!valeric acid as a white foam; MS: m/e 870.8 M+H-MeOH!, 888.7 M+H-CH₃ !, 889.7 M-CH₃ !902.7 M+H!, 924.7 M+Na!.

viii) 5.4g (5.4mmol) of 4-methylbenzhydrylamine resin were swollen in 30 mlof dimethylformamide, excess solvent was drained from the resin and it was then washed twice with 20 ml dimethylformamide/N-methylmorpholine (9:1). The resin was then resuspended in 10 ml of dimethylformamide containing 4.98 g (5.4 mmol) of 5- 4- N- N- N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-valyl!-L-leucyl!-N- 3,3,3-trifluoro-1(RS)-dimethoxymethyl)propyl!amino!methyl-3,5-dimethoxyphenoxy!-valeric acid and 1.74 g (5.4 mmol) of 2-(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoraborate. Theretothere were added 1.18 ml (10.8 mmol) of N-methylmorpholine dissolved in 10 ml of dimethylformamide. The resulting mixture was agitated for 2 hours and the resin was then drained and washed five times with 30 ml of dimethylformamide. The resin was then resuspended in 30 ml of dimethylformamide containing 2.03 ml (21.6 mmol) of acetic anhydride and 2.96 ml (27 mmol) of N-methylmorpholine. This mixture was agitated for 30 minutes and the resin was then drained and washed five times with 30 ml ofdimethylformamide each time. The resin was resuspended in and agitated in 30 ml of dimethylformamide/piperidine (4:1). After 5 minutes the resin wasdrained, resuspended and again agitated in the foregoing dimethylformamide/piperidine mixture for a further 5 minutes. The resin was then drained and washed five times with 30 ml of dimethylformamide.

ix) A solution of 3.2 g (8.1 mmol) of N- (9-fluorenyl)methoxycarbonyl!-3-(2-methylphenyl)-L-alanine and 2.17 g (6.75 mmol) of 2-(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate in 22 ml of dimethylformamide was added to the resin from paragraph viii) and subsequently 1.5 ml (13.5 mmol) of N-methylmorpholine were added. The mixture was agitated for 30 minutes andthen the resin was drained and washed five times with 30 ml of dimethylformamide, twice with 30 ml of dichloromethane, twice with 30 ml of ethyl acetate and twice with 30 ml of diethyl ether. After drying therewere obtained 8.95 g of 5- 4- N- N- N- (9-fluorenyl)methoxycarbonyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!-N- 3,3,3-trifluoro-1(RS)-(dimethoxymethyl)propyl!amino!methyl!-3,5-dimethoxyphenoxy!-N-(4-methyl-α-(RS)-phenylbenzyl)valeramide-polystyrene conjugate as a pale brown solid (0.31 mmol/g loading estimated by quantitation of dibenzofulvene at 301 nm).

EXAMPLE 5

0.236 g (0.215 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl!-L-leucinamide was dissolved in 1.5 ml of water, 13.5 ml of trifluoroacetic acid and 7 ml of dichloromethane and the solution was stirred at room temperature for 1 hour and then left to stand at 4°C. for 18 hours. The solution was then diluted with toluene and evaporated.The residue was triturated with diethyl ether and the resulting solid was filtered off. The solid was purified by RP-HPLC on a Dynamax C18 column (5micron, 300 Å, 21.4 mm×50 mm). The elution gradient comprised 95%SSA:5% SSB to 95%:SSB 5% SSA over 6 minutes and there were obtained, after lyophilization, 69 mg of 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-butenylboronic acid as a foam; MS: m/e 847 M+H!.

The starting material was prepared as follows:

i) 2 g (9.48 mmol) of 2-(dichloromethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane were dissolved in 30 ml of tetrahydrofuran and the solution was cooled under a nitrogen atmosphere to -78° C. 9.5 ml (9.5 mmol) of 1M allylmagnesium bromide were added dropwise and the solution was stirred at room temperature for 18 hours. The solution was partitioned between ethyl acetate, saturated sodium chloride solution and 2M hydrochloric acid solution. The aqueous layer was extracted with ethyl acetate and the organic layers were combined and dried over anhydrous sodium sulphate. After filtration and evaporation the oil obtained was distilled to give 1.45 g of 2-(1(RS)-chloro-3-butenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane; b.p. 53° C./0.4 mm Hg.

ii) 6.6 ml (6.6 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise to a solution of 1.43 g (6.6 mmol) of 2-(1(RS)-chloro-3-butenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 20 ml of tetrahydrofuran under nitrogen at -78° C. The solution was then stirred overnight at room temperature. The solvent was removed by evaporation and the residue was taken up in diethyl ether. Insoluble material was removed by filtration and the filtrate was cooled to 0° C. 1.5 ml (19.8 mmol) of trifluoroacetic acid were added and thesolution was stirred at 0° C. for 30 minutes. The resulting precipitate was filtered off and dried to give 0.5 g of α-(RS)-allyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate which was used in the next step without further purification.

iii) 0.25 g (0.27 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine was dissolved in 4 ml of dimethylformamide and 4 ml of dichloromethane. 0.15 ml (1.6 mmol) of N-methylmorpholine was added and the solution was cooled to -15° C. under a nitrogen atmosphere. 50 mg (0.38 mmol) of isobutyl chloroformate were added and the solution was stirred for 10 minutes at -15° C. 0.1 g (0.32 mmol) of α-(RS)-allyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate was added and the mixture was stirred at room temperaturefor 18 hours. After evaporation the residue was partitioned between ethyl acetate and 2M hydrochloric acid. The organic layer was washed with 2M hydrochloric acid, water and saturated sodium chloride solution and then dried over anhydrous sodium sulphate. After evaporation there was obtained0.3 g of N2-N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl!-L-leucinamide in the form of a solid; MS: m/e 1097 M+H!.

EXAMPLE 6

0.25 g (0.23 mmol) of N2-N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl!-L-leucinamide was dissolved in 1.5 ml of water, 13.5 ml of trifluoroacetic acid and 7 ml of dichloromethane and the solution was stirred at room temperature for 1 hour and then left to stand at 4° C. for 18 hours. The solution was diluted with toluene and evaporated. The residue was triturated with diethyl ether and the resulting solid was filtered off. The solid was purified by RP-HPLC on an Aquapore octyl column (20 micron, 100 mm×10 mm). The elution gradient comprised 95% SSA:5% SSBto 5% SSA:95% SSB over 6 minutes and there were obtained, after lyophilization, 92 mg of 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!propylboronic acid as a foam; MS: m/e 835 M+H!.

The starting material was prepared as follows:

i) 2.64 g (12.5 mmol) of 2-(dichloromethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane were dissolved in 30 ml of tetrahydrofuran and the solution was cooled under a nitrogen atmosphere to -78° C. 11.8 ml (12.5 mmol) of 1.06M ethylmagnesium bromide were added dropwise and the solution was stirred at room temperature for 18 hours. The solution was partitioned between ethyl acetate, saturated sodium chloride solution and 2M hydrochloric acid solution. The aqueous layer was extracted with ethyl acetate and the organic layers were combined and dried over anhydrous sodium sulphate. After filtration and evaporation the oil obtained was distilled to give 2.04 g of 2- 1(RS)-chloropropyl!-4,4,5,5-tetramethyl-1,3,2-dioxaborolane; b.p. 53° C./0.8 mm Hg.

ii) 10 ml (10 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise to a solution of 2.03 g (9.9 mmol) of 2- 1(RS)-chloropropyl!-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 20 ml tetrahydrofuran under a nitrogen atmosphere at -78° C. The solutionwas then stirred overnight at room temperature. The solvent was removed by evaporation and the residue was taken up in diethyl ether. Insoluble material was removed by filtration and the filtrate was cooled to 0° C. 2.3 ml (30 mmol) of trifluoroacetic acid were added and the solution was stirred at 0° C. for 30 minutes. The resulting precipitate was filtered off and dried to give 0.5 g of α-(RS)-ethyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate as a white solid.

Analysis for C₁₁ H₂₁ BNF₃ O₄ 299.15!. Calculated: C, 44.17; H, 7.08; N, 4.68% Found: C, 44.06, H, 7.05, N, 4.71%.

iii) 0.25 g (0.27 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine was dissolved in 2 ml of dimethylformamide and 5 ml of dichloromethane. 0.15 ml (1.6 mmol) of N-methylmorpholine was added and the solution was cooled to -15° C. under a nitrogen atmosphere. 50 mg (0.38 mmol) of isobutyl chloroformate were added and the solution was stirred for 10 minutes at -15° C. 0.1 g (0.33 mmol) of α-(RS)-ethyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate was added and the mixture was stirred at room temperaturefor 18 hours. After evaporation the residue was partitioned between ethyl acetate and 2M hydrochloric acid. The organic layer was washed with 2M hydrochloric acid, water and saturated sodium chloride solution and then dried over anhydrous sodium sulphate. After evaporation there was obtained0.26 g of N2-N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-gl utamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl!-L-leucinamide in the form of a solid; MS: m/e 1085 M+H!.

EXAMPLE 7

0.16 g (14.6 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl!-L-leucinamide was dissolved in 4 ml of trifluoroacetate acid and 4 ml of dichloromethane. 4 drops of water were added and the solution was stirred at room temperature for 3 hours. The residue was triturated with diethyl ether and the resulting solid was filtered off and dried to give, after lyophilization, 139 mg of 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!butylboronic acid as a foam; MS: m/e 849 M+H!.

The starting material was prepared as follows:

i) 0.5 g (2.37 mmol) of 2-(dichloromethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was dissolved in 10 ml of tetrahydrofuran and the solution was cooled under a nitrogen atmosphere to -78° C. 2.4 ml (2.4 mmol) of 1M propylmagnesium bromide were added dropwise and the solution was stirred at room temperature for 18 hours. The solution was partitioned between ethyl acetate, saturated sodium chloride solution and 2M hydrochloric acid solution. The aqueous layer was extracted with ethyl acetate and the organic layers were combined and dried over anhydrous sodium sulphate. After evaporation there was obtained 0.38 g of 2- 1(RS)-chlorobutyl!-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as an oil which was used in the next step without further purification.

ii) 1.7 ml (1.7 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise to a solution of 0.37 g (1.69 mmol) of2- 1(RS)-chlorobutyl!-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 20 ml of tetrahydrofuran under nitrogen at -78° C. The solution was then stirred overnight at room temperature. The solvent was removed by evaporation and the residue was taken up in diethyl ether. Insoluble material was removed by filtration and the filtrate was cooled to 0° C. 0.39 ml (5.1 mmol) of trifluoroacetic acid was added and the solution was stirred at 0° C. for 30 minutes. The solution was evaporated and the residue was co-evaporated with toluene to give 0.62 g of α-(RS)-propyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate as a brown oil which was used in the next step without further purification.

iii) 0.2 g (0.218 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine was dissolved in 2 ml of dimethylformamide and 6 ml of dichloromethane. 0.12 ml (1.1 mmol) of N-methylmorpholine was added and the solution was cooled to -15° C. under a nitrogen atmosphere. 40 mg (0.31 mmol) of isobutyl chloroformate were added and the solution was stirred for 10 minutes at -15° C. 0.14 g (0.44 mmol) of α-(RS)-propyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate was added and the mixture was stirred at room temperaturefor 66 hours. After evaporation the residue was partitioned between ethyl acetate and 2M hydrochloric acid. The organic layer was washed with 2M hydrochloric acid, water and saturated sodium chloride solution and then dried over anhydrous sodium sulphate. After evaporation there was obtained0.17 g of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl!-L-leucinamide in the form of a solid; NMR (DMSO, 400 MHz) δ: 0.75-0.9 (m,17 H), 1.01-1.08 (m,6 H), 1.15-1.25 (m,1 H), 1.35 9s,36 H), 1.4-1.7 (m,4 H), 1.75-1.8 (m,1 H), 2.05-2.15 (m,2 H), 2.23 (s,3 H), 2.29-2.41 (m,6H), 2.55-2.6 (m,1 H), 2.7-2.74 (m,1 H), 2.95-3.05 (m,1 H), 4.15-4.25 (m,3 H), 4.48-4.55 (m,₁ H), 4.6-4.7 (m,1 H), 7.05-7.11 (m,4 H), 7.7-7.81 (m,2 H), 8.05-8.12 (m,2 H), 8.15-8.25 (m,2 H).

EXAMPLE 8

0.126 g (0.116 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1 3,3-difluoro- 1(S)-(dimethoxymethyl)-butyl!-L-leucinamide was dissolved in 5 ml of trifluoroacetic acid and 5 ml of dichloromethane. A few drops of water were added and the solution was stirred at room temperature for 1 hour. The residue was evaporated, the residue was triturated with diethyl ether and the resulting solid was filtered off. The solid was purified by chromatography on silica gel using dichloromethanelmethanol/acetic acid/water (75:15:3:2) for the elution. There were obtained 67 mg of 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4-difluorovaleraldehyde as a cream colouredsolid of melting point 128°-130° C.

The starting material was prepared as follows:

i) 1.5 g (4.62 mmol) of 4,4-difluoro-L-norvaline p-toluenesulphonate were dissolved in dimethylformamide. 1.71 g (7.85 mmol) of di-tert-butyl dicarbonate and 3.23 ml (23.25 mmol) of triethylamine were added and the solution was stirred at 60° C. for 3 hours. The solution was evaporated and the residue was partitioned between ethyl acetate and 2M hydrochloric acid. The organic layer was dried over anhydrous sodium sulphate and evaporated. The resulting oil was purified by chromatography on silica gel using ethyl acetate for the elution. There were obtained 1.16 g of N-(tert-butoxycarbonyl)-4,4-difluoro-L-norvaline as an orange oil which was used directly in the next step.

ii) 1.16 g (4.62 mmol) of N-(tert-butoxycarbonyl)-4,4-difluoro-L-norvaline were dissolved in 30 ml of dichloromethane. 6.4 ml (46.2 mmol) of triethylamine, 564 mg (4.62 mmol) of N,N-dimethylaminopyridine, 1.77 g (9.24 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochlorideand 1.8 g (18.5 mmol) of N,O-dimethylhydroxylamine hydrochloride were addedand the solution was stirred at room temperature for 18 hours. The mixture was diluted with ethyl acetate, washed with 2M hydrochloric acid and aqueous sodium hydrogen carbonate solution, dried over anhydrous sodium sulphate and evaporated to give an oil which was purified by chromatography on silica gel using ethyl acetate for the elution. There were obtained 547 mg of N,O-dimethyl 2(S)-(tert-butoxyformamido)-4,4-difluorovalerohydroxamate as a colourless oil; MS: m/e 297 M+H!.

iii) 547 mg (1.85 mmol) of N,O-dimethyl 2(S)-(tert-butoxyformamido)-4,4-difluorovalerohydroxamate were dissolved in 12 ml of tetrahydrofuran and the solution was stirred at 0° C. 1.76 ml (1.76 mmol) of 1M lithium aluminium hydride in tetrahydrofuran were added and the solution was stirred for 15 minutes. The mixture was partitioned between ethyl acetate and saturated aqueous potassium hydrogensulphate solution. The organic layer was evaporated and the residue was dissolved in freshly prepared methanolic hydrogen chloride solution. After1 hour the solution was evaporated to give 372 mg of 3,3-difluoro-1(S)-(dimethoxymethyl)butylamine hydrochloride as a white solid; MS: m/e 184 M+H!.

iv) 0.3 g (0.33 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine was dissolved in 15 ml of dichloromethane. 0.22 ml (1.98mmol) of N-methylmorpholine, 96 mg (0.5 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 45 mg (0.33 mmol) of hydroxybenzotriazole and 217 mg (0.99 mmol) of 3,3-difluoro-1(S)-(dimethoxymethyl)butylamine hydrochloride were added andthe solution was stirred at room temperature for 18hours. The mixture was washed with 2M hydrochloric acid and aqueous sodium hydrogen carbonate solution, dried over anhydrous sodium sulphate and evaporated. The residuewas triturated with diethyl ether and the resulting solid was filtered off and dried. There were obtained 143 g of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 3,3-difluoro-1(S)-dimethoxymethyl)butyl!-L-leucinamide; MS: m/e 1106 M+Na!⁺.

EXAMPLE 9

80 mg (0.075 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(R)-dimethoxymethyl)-2-(methylthio)ethyl!-L-leucinamide were dissolved in 10 ml of trifluoroacetic acid/dichloromethane (1:1) containing 3 drops of water and the solution was stirred for 90 minutes under a nitrogen atmosphere. The solution was evaporated to dryness under a vacuum and the residue was re-evaporated twice with toluene. The solid was triturated with 10 ml of diethyl ether to give 60 mg of 2(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-(methylthio)propionaldehyde as a white solid; MS: m/e 851.5 M+H!⁺.

The starting material was prepared as follows:

i) 2 g (8.51 mmol) of N-(tert-butoxycarbonyl)-S-methyl-L-cysteine were dissolved in 60 ml of anhydrous tetrahydrofuran and then 1.81 g (11.9 mmol) of 1-hydroxybenzotriazole hydrate, 2.28 g (11.88 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.16 g (11.90mmol) of N,O-dimethylhydroxylamine hydrochloride and 5.9 ml (33.87 mmol) ofN,N-diisopropylethylamine were added. The mixture was stirred overnight at room temperature. The solvent was removed by evaporation and the residue was partitioned between ethyl acetate and 5% (w/v) aqueous citric acid. The organic phase was washed with saturated aqueous sodium bicarbonate solution and then with saturated sodium chloride solution, dried over magnesium sulphate and evaporated under a vacuum to give 2.27 g of N,O-dimethyl 2(R)-(tert-butoxyformamido)-3-(methylthio)propionohydroxamateas a colourless oil; MS: m/e 279 M+H!⁺.

ii) 2.22 g (7.90 mmol) of N,O-dimethyl 2(R)-(tert-butoxyformamido)-3-(methylthio)propionohydroxamate were dissolved in 25 ml of anhydrous tetrahydrofuran and the solution was cooled to 0° C. 4.69 ml (4.69 mmol) of a 1M solution of lithium aluminium hydride in tetrahydrofuran were added dropwise and the mixture was stirred for 15 minutes. The reaction was quenched by the dropwise addition of saturated aqueous potassium hydrogen sulphate solution and then 50 ml of diethyl ether were added. The mixture was stirred vigorouslyfor 20 minutes. The organic phase was separated, washed with saturated aqueous sodium bicarbonate solution, dried over magnesium sulphate and evaporated to give 1.75 g of aldehyde which, without further purification,was dissolved in 20 ml of saturated methanolic hydrogen chloride solution and stirred for 2 hours under a nitrogen atmosphere at room temperature. The solvent was removed by evaporation and the residue was re-evaporated twice with toluene to give 1.3 g of dimethyl acetal as a colourless oil.

90 mg (0.45 mmol) of the dimethyl acetal were dissolved in 40 ml dichloromethane and then 200 mg (0.22 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine, 100 mg (0.87 mmol) of N-ethylmorpholine, 40 mg (0.26 mmol) of 1-hydroxybenzotriazole hydrate and 50 mg (0.26 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added. The solution was stirred overnight at room temperature. The organic phase was washed with 5% (w/v) aqueous citric acid and then with saturated aqueous sodium bicarbonate solution, dried over magnesium sulphate and evaporated under a vacuum. The resulting oil was triturated with 10 ml of diethyl ether to give 165 mg of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(dimethoxymethyl)-2-(methylthio)ethyl!-L-leucinamide as a white solid; MS: m/e 1065.7 M+H!⁺.

EXAMPLE 10

50 mg (0.048 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(S)-(dimethoxymethyl)-3-butenyl!-L-leucinamide were dissolved in 4 ml of trifluoroacetic acid/dichloromethane (1:1) containing3 drops of water and the solution was stirred for 1 hour under nitrogen. The solution was evaporated to dryness under a vacuum and the residue was re-evaporated twice with toluene. The solid was triturated with 10 ml of diethyl ether to give 30 mg of 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-pentenaldehyde; MS: m/e 831.5 M+H!⁺.

The starting material was prepared as follows:

i) 1.13 g (7.46 mmol) of L-allylglycine hydrochloride were dissolved in 20 ml of saturated aqueous sodium bicarbonate solution and 20 ml of dioxan. 1.95 g (8.93 mmol) of di-tert-butyl dicarbonate were added and the solution was stirred overnight and then evaporated to dryness under a vacuum. The residue was partitioned between diethyl ether and water. The aqueous phase was acidified with 2M hydrochloric acid and extracted with ethyl acetate. The organic phase was dried over magnesium sulphate and evaporated under a vacuum to give 1.6 g of N-(tert-butoxycarbonyl)-L-allylglycine as a colourless oil. ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s,9 H), 2.4-2.7 (m,2 H), 4.3-4.5 (m,1 H), 5.0 (br.d,1 H), 5.1-5.2 (m,2 H), 5.6-5.8 (m,1 H)

ii) N,O-Dimethyl 2(S)-(tert-butoxyformamido)-4-pentenohydroxamate was obtained in a manner analogous to that described in Example 10 i) from 1.6g (7.44 mmol) of N-(tert-butoxycarbonyl)-L-allylglycine, 1.4 g (10.4 mmol) of 1-hydroxybenzotriazole, 1.99 g (10.4 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.02 g (10.46mmol) of N,O-dimethylhydroxylamine hydrochloride and 2.6 ml (14.93 mmol) ofethyl diisopropylamine. This gave 1.9 g of product as a colourless oil. ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s,9 H), 2.3-2.6 (m,2 H), 3.2 (s,3 H), 3.8 (s,3 H), 4.6-4.7 (m,1 H), 5.0-5.4 (m,3 H), 5.6-5.8 (m,1 H).

iii) 1.9 g (7.36 mmol) of N,O-dimethyl 2(S)-(tert-butoxyformamido)-4-pentenohydroxamate were dissolved in 20 ml of anhydrous tetrahydrofuran and the solution was cooled to 0° C. 5.40 ml (5.4 mmol) of a 1M solution of lithium aluminium hydride in tetrahydrofuran were added dropwise and the mixture was stirred for 25 minutes. The reaction was quenched by the dropwise addition of saturated aqueous potassium hydrogen sulphate and then 50 ml of diethyl ether were added. The mixture was stirred vigourously for 20 minutes. The organic phase was separated, washed with saturated aqueous sodium bicarbonate solution, dried over magnesium sulphate and evaporated to give the aldehyde which, without further purification, was dissolved in 25 ml of saturated methanolic hydrogen chloride solution and stirred for 2 hours atroom temperature. The solvent was removed by evaporation and the residue was re-evaporated twice with toluene to give the amino acid acetal as a brown oil.

iv) 40 mg (0.22 mmol) of the amino acid acetal were dissolved in 4 ml of dichloromethane and then 200 mg (0.22 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine, 0.1 ml (0.78 mmol) of N-ethylmorpholine, 35 mg (0.22 mmol) of 1-hydroxybenzotriazole monohydrate and 50 mg (0.26 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added. The solution was stirred overnight at room temperature. The organic phase was washed with 5% (w/v) aqueous citric acid solution and then with saturated aqueous sodium bicarbonate solution, dried over magnesium sulphate and evaporated under a vacuum. The resulting oil was triturated with 10 ml of diethyl ether to give 148 mg of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-butenyl!-L-leucinamide as a white solid; MS: m/e 1013.6 M+H-MeOH!⁺.

EXAMPLE 11

90 mg (0.081 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 2-(butylthio)-1(R)-(dimethoxymethyl)ethyl!-L-leucinamide were dissolved in 10 ml of trifluoroacetic acid/dichloromethane (1:1) containing 3 drops of water and the solution was stirred for 90 minutes under nitrogen. The solution was evaporated to dryness under a vacuum and the residue was re-evaporated twice with toluene. The solid was trituratedwith 10 ml of diethyl ether to give 80 mg of 2(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-(butylthio)propionaldehyde as a white solid. MS: m/e 893.4 M+H!⁺.

The starting material was prepared as follows:

i) 2 g (16.53 mmol) of L-cysteine were dissolved in 40 ml of water/ethanol (1:1) together with 1.33 g (33.25 mmol) of sodium hydroxide pellets. 3.04g(16.53mmol) of butyl iodide were added and the mixture was stirred for 2 hours. The resulting S-alkylated product was treated with 3.96 g (18.14 mmol) of di-tert-butyl dicarbonate and the mixture was stirred for 1 hour.A further 3.61 g (16.53 mmol) of di-tert-butyl dicarbonate were added and the mixture was stirred overnight. The solution was evaporated to dryness under a vacuum and the residue was partitioned between diethyl ether and saturated aqueous sodium hydrogen carbonate solution. The aqueous phase was acidified by partitioning in 2M hydrochloric acid and ethyl acetate, the separated organic phase was dried over magnesium sulphate and the solvent was removed by evaporation to give 4.3 g of N-(tert-butoxycarbonyl)-S-butyl-L-cysteine as a brown oil; ¹ H NMR (250 MHz, CDCl₃) δ: 0.9 (t,3 H), 1.3-1.6 (m,4 H), 1.4 (s,9 H), 2.55 (t,2 H), 3.0 (br.d,2 H), 4.5 (m,1 H), 5.3 (br.d, 1 H).

ii) N,O-Dimethyl 2(R)-(tert-butoxyformamido)-3-(butylthio)-propionohydroxamate was obtainedin a manner analogous to that described in Example 10 i) from 2.15 g (7.76 mmol) of N-(tert-butoxycarbonyl)-S-butyl-L-cysteine, 1.19 g (7.77 mmol) of1-hydroxybenzotriazole monohydrate, 2.24 g (11.68 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.14 g (11.68mmol) of N,O-dimethylhydroxylamine hydrochloride and 1.34 g (11.64 mmol) ofN-ethylmorpholine in 30 ml of dichloromethane. This gave 2.0 g of product as a colourless oil after column chromatography using ethyl acetate/petrol(1:2) as the eluent. ¹ H NMR (250 MHz, CDCl₃) δ: 0.9 (t,3 H), 1.3-1.6 (m,4 H), 1.4 (s,9 H), 2.55 (t,2 H), 2.6 -2.7 (dd,1 H), 2.8-2.9(dd,1 H), 3.2 (s,3 H), 3.75 (s,3 H), 4.8-4.9 (m,1 H), 5.3 (br.d,1 H).

iii) 0.3 g (0.94 mmol) of N,O-dimethyl 2(R)-(tert-butoxyformamido)-3-(butylthio)propionohydroxamate was dissolvedin 10 ml of anhydrous tetrahydrofuran and the solution was cooled to 0° C. 0.55 ml (0.55 mmol) of a 1M solution of lithium aluminium hydride in tetrahydrofuran was added dropwise and the mixture was stirred for 15 minutes. The reaction was quenched by the dropwise addition of saturated aqueous potassium hydrogen sulphate and then 20 ml of diethyl ether were added. The mixture was stirred vigorously for 20 minutes. The organic phase was separated, washed with saturated aqueous sodium bicarbonate solution, dried over magnesium sulphate and evaporated to givethe aldehyde which, without further purification, was dissolved in 20 ml ofsaturated methanolic hydrogen chloride solution and stirred for 2 hours under a nitrogen atmosphere at room temperature. The solvent was removed by evaporation and the residue was re-evaporated twice with toluene to give the amino acid acetal as a brown oil.

200 mg (0.82 mmol) of the amino acid acetal were dissolved in 40 ml of dichloromethane and then 200 mg (0.22 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl) propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine, 100 mg (0.87 mmol)of N-ethylmorpholine, 40 mg (0.26 mmol) of 1-hydroxybenzotriazole and 50 mg(0.26 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added. The solution was stirred for 2 hours at room temperature. The organic phase was washed with 5% (w/v) aqueous citric acid solution and then with saturated aqueous sodium bicarbonate solution, dried over magnesium sulphate and evaporated under a vacuum. The resulting oil was triturated with 10 ml of diethyl ether to give 160 mg of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 2-(butylthio)- 1(R)-(dimethoxymethyl)-ethyl!-L-leucinamide asa white solid; MS: m/e 1075.6 M+H-MeOH!⁺.

EXAMPLE 12

56 mg (0.049 mmol) of N1- 2-(benzylthio)-1(R)-(dimethoxymethyl)ethyl!-N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-.alpha.-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucinamide were dissolved in 10 ml of trifluoroacetic acid/dichloromethane (1:1) containing 3 drops of water and the solution was stirred for 90 minutes. The solution was evaporated to dryness under a vacuum and the residue was re-evaporated twice with toluene. The solid was triturated with 10 ml of diethyl ether to give 40 mg of 3-(benzylthio)-2(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!propionaldehyde as a white solid. MS: m/e 927.6 (M+H!⁺.

The starting material was prepared as follows:

i) S-Benzyl-N-(tert-butoxycarbonyl)-L-cysteine was obtained in a manner analogous to that described in Example 10 i) from 1 g (4.74 mmol) of S-benzyl-L-cysteine, 0.8 g (9.5 mmol) of sodium bicarbonate and 1.4 g (6.4mmol) of di-tert-butyl dicarbonate. There were obtained 1.4 g of a colourless oil; ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s,9 H), 2.8-2.9 (m,2 H), 3.7 (s,2 H), 4.4-4.5 (m,1 H), 5.3 (d,1 H), 7.2-7.4 (m,5 H)

ii) N,O-Dimethyl 3-(benzyl)-2(R)-(tert-butoxyformamido)-propionohydroxamatewas obtained in a manner analogous to that described in Example 9 i) from 1.4 g (4.52 mmol) of S-benzyl-N-(tert-butoxycarbonyl)-L-cysteine, 0.70 g (4.6 mmol) of 1-hydroxybenzotriazole monohydrate, 1.30 g (6.77 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 0.66 g (6.77 mmol) of N,O-dimethylhydroxylamine hydrochloride and 0.78 g (6.77 mmol) ofN-ethylmorpholine in 40 ml of dichloromethane.

There were obtained 0.60 g of a colourless oil; ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s,9 H), 2.55-2.65 (dd,1 H), 2.75-2.85, (dd,1 H),3.2 (s,3 H), 3.7 (s,3 H), 3.72 (s,2 H), 4.9 (m,1 H), 5.3 (d,1 H), 7.2 -7.35(m,5 H).

iii) 0.48 g (1.36 mmol) of N,O-dimethyl 3-(benzyl)-2(R)-(tert-butoxyformamido)propionohydroxamate was dissolved in10 ml of anhydrous tetrahydrofuran and the solution was cooled to 0°C. 0.95 ml (0.95 mmol) of a 1M solution of lithium aluminium hydride in tetrahydrofuran was added dropwise and the mixture was stirred for 15 minutes. The reaction was quenched by the dropwise addition of saturated aqueous potassium hydrogen sulphate and then 20 ml of diethyl ether were added. The mixture was stirred vigorously for 20 minutes. The organic phase was separated, washed with saturated aqueous sodium bicarbonate solution, dried magnesium sulphate and evaporated to give the aldehyde which, without further purification, was dissolved in 10 ml of saturated methanolic hydrogen chloride solution and stirred for 2 hours at room temperature. The solvent was removed by evaporation and the residue was re-evaporated twice with toluene to give the amino acid acetal as a brown oil.

100 mg (0.36 mmol) of the amino acid acetal were dissolved in 40 ml of dichloromethane and then 200 mg (0.22 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine, 100 mg (0.87 mmol) of N-ethylmorpholine, 40 mg (0.30 mmol) of 1-hydroxybenzotriazole and 50 mg (0.26 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added. The solution was stirred overnight at room temperature. The organic phase was washed with 5% (w/v) aqueous citric acid solution and then with saturated aqueous sodium bicarbonate solution, dried over magnesium sulphate and evaporated under a vacuum. The resulting oil was triturated with 10 ml of diethyl ether to give 160 mg of N1- 2-(benzylthio)-1(R)-(dimethoxymethyl)ethyl!-N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α--aspartyl!-O-tert-butyl-L-.alpha.-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucinamide asa white solid; MS: m/e 1109.8 M+H-MeOH!⁺.

EXAMPLE 13

49 mg (0.046 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-pentynyl!-L-leucinamide were dissolved in 4 ml of trifluoroacetic acid/dichloromethane (1:1) containing3 drops of water and the solution was stirred for 1 hour under a nitrogen atmosphere. The solution was evaporated to dryness under a vacuum and the residue was re-evaporated twice with toluene. The solid was triturated with 10 ml of diethyl ether to give 30 mg of 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-hexynal as a white solid; MS: m/e 843.6 M+H!⁺.

The starting material was prepared as follows:

i) N-(tert-Butoxycarbonyl)-L-(2-butynyl)glycine was obtained in a manner analogous to that described in Example 10 i) from 1.0 g (7.80 mmol) of L-(2-butynyl)glycine (prepared according to Sasaki et al. Int. J. Peptide Protein Res 1986, 27, 360-365), 2.66 g (31.7 mmol) of sodium bicarbonate and 1.89 g (8.66 mmol) of di-tert-butyl dicarbonate. There was obtained 1.94 g of a colourless oil; ¹ H NMR (250 MHz, CDCl₃) δ: 1.45 (s,9 H), 1.75 (t,3 H), 2.6-2.9 (m,2 H), 4.4-4.5 (m,1 H), 5.3 (br.d,1 H).

ii) N,O-Dimethyl 2(S)-(tert-butoxyformamido)-4-hexynohydroxamate was obtained in a manner analogous to that described in Example 9 i) from 1.74g (7.67 mmol) of N-(tert-butoxycarbonyl)-L-(2-butynyl)glycine, 1.45 g (9.5 mmol) of 1-hydroxybenzotriazole, 2.06 g (10.73 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.05 g (10.77mmol) of N,O-dimethylhydroxylamine hydrochloride and 5.3 ml (30.43 mmol) ofethyldiisopropylamine in 80 ml of tetrahydrofuran. There were obtained 2.0 g of a colourless oil; ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s,9 H), 1.75 (t,3 H), 2.55 (m,2 H), 3.2 (s,3 H), 3.5 (s,3 H), 4.7-4.8 (m,1 H), 5.35 (br.d,1 H).

iii) 1.0 g (3.70 mmol) of N,O-dimethyl 2(S)-(tert-butoxyformamido)-4-hexynohydroxamate was dissolved in 10 ml of anhydrous tetrahydrofuran and the solution was cooled to 0° C. 2.59ml (2.59 mmol) of a 1M solution of lithium aluminium hydride in tetrahydrofuran were added dropwise and the mixture was stirred for 30 minutes. The reaction was quenched by the dropwise addition of 20 ml of saturated aqueous potassium hydrogen sulphate and then 50 ml of diethyl ether were added. The mixture was stirred vigorously for 30 minutes. The organic phase was separated, washed with saturated aqueous sodium bicarbonate solution, dried over magnesium sulphate and evaporated to givethe aldehyde which, without further purification, was dissolved in ml of saturated methanolic hydrogen chloride solution and stirred for 2 hours under a nitrogen atmosphere at room temperature. The solvent was removed by evaporation and the residue was re-evaporated twice with toluene to give the amino acid acetal as a brown oil.

47 mg (0.24 mmol) of the amino acid acetal were dissolved in 20 ml of dichloromethane and then 200 mg (0.22 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert- butyl-L-α-glutamyl!-2-methyl-L-phenyl alanyl!-3-methyl-L-valyl!-L-leucine, 0.1 ml (0.78 mmol) of N-ethylmorpholine, 42 mg (0.27 mmol) of 1-hydroxybenzotriazole and 59 mg (0.31 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloridewere added. The solution was stirred overnight at room temperature. The organic phase was washed with 5% (w/v) aqueous citric acid solution and then with saturated aqueous sodium bicarbonate solution, dried over magnesium sulphate and evaporated under a vacuum. The resulting oil was triturated with 10 ml of diethyl ether to give 110 mg of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-pentynyl!-L-leucinamide as a white solid. MS: m/e 1025.8 M+H-MeOH!⁺.

EXAMPLE 14

0.065 g (0.06 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(dimethoxymethyl)-2-(3-thienyl)ethyl!-L-leucinamide wasdissolved in 10 ml of dichloromethane/trifluoroacetic acid (1:1) containing3 drops of water. The solution was stirred for 3 hours at room temperature.After removal of the solvent by evaporation the crude product was chromatographed on silica gel using dichloromethane:methanol:acetic acid:water (120:15:3:2) as the eluent to give 0.035 g of 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3(3-thienyl)propionaldehyde as a white solid; MS: m/e 887.7 M+H!⁺.

The starting material was prepared as follows:

i) 0.5 g (2.92 mmol) of 3-(3-thienyl)-DL-alanine was dissolved in 15 ml of water and 15 ml of dioxan. 2.5 g (29.76 mmol) of sodium hydrogen carbonateand 3.53 g (16.19 mmol) of di-tert-butyl dicarbonate were added and the solution was stirred for 2 hours and then evaporated to dryness under a vacuum. The residue was partitioned between diethyl ether and saturated aqueous sodium hydrogen carbonate solution. The aqueous phase was acidified with 2M hydrochloric acid and extracted with ethyl acetate. The organic phase was dried over magnesium sulphate and the solvent was evaporated under a vacuum to give 0.685 g of N-(tert-butoxycarbonyl)-3-(3-thienyl)-DL-alanine as a colourless oil; ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s,9 H), 2.9 (dd,1 H), 3.15 (dd,1 H), 4.3 (m,1 H), 7.0 (d,1 H), 7.1 (br s,H), 7.3 (m,1 H).

ii) 0.69 g (2.55 mmol) of N-(tert-butoxycarbonyl)-3-(3-thienyl)-DL-alanine was dissolved in 40 ml of dichloromethane. 0.34 g (3.56 mmol) of N,O-dimethylhydroxylamine hydrochloride, 0.54 g (3.53 mmol) of 1-hydroxybenzotriazole monohydrate, 0.68 g (3.55 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1.0 g (8.70 mmol) of 4-ethylmorpholine were added and the resulting solution wasstirred at room temperature overnight. The solution was then washed with 5%citric acid solution, saturated sodium hydrogen carbonate solution and saturated sodium chloride solution and dried over anhydrous magnesium sulphate. After evaporation of the solvent the crude product was chromatographed on silica gel using 30% ethyl acetate in petroleum ether as the eluent to give 0.75 g of N,O-dimethyl 2(RS)-(tert-butoxyformamido)-3-(3-thienyl)propionohydroxamate as a white solid; ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s,9 H), 2.95 (dd,1H), 3.05 (dd,1 H), 3.15 (s,3 H), 3.65 (s,3 H), 4.9 (m,1 H), 5.15 (br d,1 H), 6.9 (d,1 H), 7.0 (d,1 H), 7.2 (m,1 H).

iii) 0.2 g (0.64 mmol) of N,O-dimethyl 2(RS)-(tert-butoxyformamido)-3-(3-thienyl)propionohydroxamate was dissolved in ml of anhydrous tetrahydrofuran and the solution was cooled to 0° C. 0.5 ml (0.5 mmol) of a 1M solution of lithium aluminium hydride in tetrahydrofuran was added dropwise and the solution was stirredfor 15 minutes. The reaction was quenched by the dropwise addition of saturated potassium hydrogen sulphate solution and then 30 ml of diethyl ether were added. The resulting two phase system was stirred vigorously for 1 hour. The organic phase was separated, washed with saturated sodium hydrogen carbonate solution and saturated sodium chloride solution, dried over magnesium sulphate and evaporated to give the aldehyde which, withoutpurification, was dissolved in 10 ml of a saturated methanolic hydrogen chloride solution and stirred at room temperature for 2 hours. After removal of the solvent by evaporation the dimethyl acetal was used in the next step without purification.

The dimethyl acetal was dissolved in 40 ml of dichloromethane and then 0.15g (0.16 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine, 0.03 g (0.2 mmol) of 1-hydroxybenzotriazole, 0.038 g (0.2 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.08 g (0.65 mmol) of N-ethylmorpholine were added and the resulting solution was stirred at room temperature for 2 hours. The solution was washed with 5% citric acid solution, saturated sodium hydrogen carbonate solution and saturated sodium chloride solution and dried over anhydrous magnesium sulphate. After removal of the solvent by evaporation the crude product was chromatographed on silica gel using 5% methanol in dichloromethane as the eluent to give 0.07 g of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(RS)-(dimethoxymethyl)-2-(3-thienyl)ethyl-L-leucinamide as a white solid; MS: m/e 1069 M+H-MeOH!⁺.

EXAMPLE 15

0.08 g (0.07 mmol) of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-2-(2-thienyl)ethyl!-L-leucinamide was dissolved in 10 ml of dichloromethane/trifluoroacetic acid (1:1) containing 3 drops of water and the solution was stirred for 2 hours at room temperature. After removal of the solvent by evaporation the crude product was chromatographed on silica gel using dichloromethane:methanol:acetic acid:water (120:15:3:2) as the eluent to give 0.021 g of 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3(2-thienyl)propionaldehyde as a white solid; MS: m/e 887.4 M+H!⁺.

The starting material was prepared as follows:

i) 0.63 g (2.33 mmol) of N-(tert-butoxycarbonyl)-3-(2-thienyl)-L-alanine was dissolved in 50 ml of dichloromethane and then 0.34 g (3.48 mmol) of N,O-dimethylhydroxylamine hydrochloride, 0.36 g (2.35 mmol) of 1-hydroxybenzotriazole monohydrate, 0.67 g (3.49 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.40 g (3.47 mmol) of N-ethylmorpholine were added. The resulting solution was stirred at room temperature overnight. The solution was washed with 5% citric acid, then with saturated sodium hydrogen carbonate solution and saturated sodium chloride solution, dried over anhydrous magnesium sulphate and evaporated to give 0.70 g of N,O-dimethyl 2(S)-(tert-butoxyformamido)-3-(2-thienyl)propionohydroxamate as a white solid; ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s,9 H), 3.1 (dd,1 H), 3.15 (s,3 H), 3.2 (dd,1 H), 3.7 (s,3 H), 4.9 (br d,1 H), 5.8 (m,1 H), 6.8 (d,1 H), 6.9 (dd,1 H), 7.15 (d,1 H).

ii) 0.4 g (1.27 mmol) of N,O-dimethyl 2(S)-(tert-butoxyformamido)-3-(2-thienyl)propionohydroxamate was dissolvedin 10 ml of anhydrous tetrahydrofuran and the solution was cooled to 0° C. 0.9 ml (0.9 mmol) of a 1M solution of lithium aluminium hydride in tetrahydrofuran was added and the resulting solution stirred for 15 minutes. The reaction was quenched by the dropwise addition of 15 ml of saturated potassium hydrogen sulphate solution and then 30 ml of diethyl ether were added. The resulting two phase system was stirred vigorously for 40 minutes. The organic phase was separated, washed with saturated sodium hydrogen carbonate solution and saturated sodium chloridesolution and dried over anhydrous magnesium sulphate. After removal of the solvent by evaporation the aldehyde, without further purification, was dissolved in 10 ml of a saturated methanolic hydrogen chloride solution and stirred at room temperature for 2 hours. After removal of the solvent by evaporation the dimethyl acetal was used in the next step without purification.

The dimethyl acetal was dissolved in 40 ml of dichloromethane and then 0.20g (0.22 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine, 0.04 mg (0.26 mmol) of 1-hydroxybenzotriazole, 0.05 g (0.26 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochlorideand 0.10 g (0.87 mmol) of N-ethylmorpholine were added. The resulting solution was stirred at room temperature for 2 hours, then washed in sequence with 5% citric acid solution, saturated sodium hydrogen carbonatesolution and saturated sodium chloride solution and dried over anhydrous magnesium sulphate.

After removal of the solvent by evaporation the crude product was triturated with diethyl ether to give 0.16 g of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-2-(2-thienyl)ethyl-L-leucinamide as a white solid. MS: m/e 1069.6 M+H-MeOH!⁺.

EXAMPLE 16

In an analogous manner to that described in Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-L-cyclohexyl-glycine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-2-cyclohexylglycyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 883.5 M+H!.

EXAMPLE 17

In an analogous manner to that described in Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-L-valine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 843.5 M+H!.

EXAMPLE 18

In an analogous manner to that described in Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-D-alanine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-alanyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 815.4 M+H!.

EXAMPLE 19

In an analogous manner to that described in Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-D-valine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 843.4 M+H!.

EXAMPLE 20

0.2 g (0.2 mmol) of N2- N- N- N- N-(carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl -L-valyl!-N1- 1(R)-(3a(S),4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)pentyl!-L-leucinamide was dissolved in 12 ml of acetone and 12 ml of 0.1M ammonium acetate in water were added. 0.21 g (1 mmol) of sodium periodate was added and the resulting mixture was stirred at room temperature for 22 hours. 7 ml of water were then added together with a small amount of sodium periodate. The resultingsolution was stirred for a further 5 hours. The acetone was removed under avacuum and the aqueous residue was acidified with 2N hydrochloric acid and then extracted with ethyl acetate. Saturated aqueous sodium chloride was added to the aqueous layer which was then extracted with ethyl acetate. The organic extracts were combined, dried over sodium sulphate and evaporated. The residue was trituated with diethyl ether, filtered off anddried to give 167 mg of 1(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!pentylboronic acid as a white solid; MS: m/e 845.4 M+H-H₂ O!⁺.

The starting material was prepared as follows:

i) In an analogous manner to that described in Example 21 i) and ii), by replacing 3-butenylmagnesium bromide with butylmagnesium bromide there wasobtained α-(R)-butyl-3a(S),4(S), 5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborole-2-methylamine trifluoroacetate (1:1) which was used in the next step without further purification.

ii) 0.25 g (0.27 mmol) of N- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine was dissolved in 2 ml of dimethylformamide and 4 ml of dichloromethane. 0.15 ml (1.4 mmol) of N-methylmorpholine was added and the solution was cooled to -10° C. under a nitrogen atmosphere. 45 mg (0.32 mmol) of isobutyl chloroformate were added and the solution was stirred for 10 minutes at -10° C. 0.2 g (0.54 mmol) of α-(R)-butyl-3a(S),4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborole-2-methylamine trifluoroacetate (1.1) was added and the mixture was stirred at room temperature for 16 hours. The solution was diluted with dichloromethane, washed with 2M hydrochloric acid and water and dried over anhydrous sodium sulphate. After evaporationthe residue was triturated with diethyl ether and dried. There was obtained0.227 g of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(3a(S), 4(S),5,6(S), 7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)pentyl!-L-leucinamide as a white solid; MS: m/e 1165.9 M+H!⁺.

iii) 300 mg (0.26 mmol) of N2- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(3a(S),4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)-4-pentenyl!-L-leucinamide were dissolved in 3.5 mlof trifluoroacetic acid and 3.5 ml of dichloromethane. The solution was stirred at room temperature for 45 minutes, then diluted with toluene and evaporated. The residue was triturated with diethyl ether and the resulting solid was filtered off and dried and then purified by chromatography on silica gel using dichlomethane/methanol/acetic acid/water (170:15:3:2) for the elution. There were obtained 135 mg of N2- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(3a(S), 4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)-4-pentenyl!-L-leucinamide as a white solid: MS: m/e 995.3 M+H!⁺.

EXAMPLE 21

N2- N- N- N- N-(3-Carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(3a(S),4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)-4-pentenyl!-L-leucinamide can be converted into N2- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-pentenylboronic acid in an analogous manner to that described in the first paragraph ofExample 20.

The starting material was prepared as follows:

i) 0.5 g (1.9 mmol) of 2-(dichloromethyl)-3a(S),4(S),5,6(S), 7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborole was dissolved in 5 ml of tetrahydrofuran and the solution was cooled to -78° C. under a nitrogen atmosphere. 4.5 ml (2.3 mmol) of 0.5M 3-butenylmagnesium bromide in tetrahydrofuran were added dropwise and the resulting solution was stirred for 2 minutes. 3 ml (1.52 mmol) of 0.5M zinc (II) chloride solution were then added and the mixture was stirred for 16 hours while slowly warming to room temperature. The mixture was diluted with ethyl acetate and then washed with 2M hydrochloric acid and brine. The organic phase was dried over sodium sulphate and then evaporated under a vacuum. The residue was purified by chromatography on silica gel using diethyl ether/hexane (1:9) for the elution to give 177 mgof 2- 1(S)-chloro-4-pentenyl!-3a(S)-4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborole. NMR: (CDCl₃) 0.83 (s, 3 H), 1.15 (d, 1 H, 1.30 (s, 3 H), 1.42 (s, 3 H), 1.42 (s, 3 H), 1.85-1.95 (m, 4H), 2.08 (t, 1 H), 2.15-2.35 (m, 4 H), 3.49 (dd, 1 H), 4.35 (dd, 1 H), 5.0 (dd, 1 H), 5.07 (dd, 1 H), 5.78 (m, 1 H). ii) 0.158 g (0.56 mmol) of 2- 1(S)-chloro-4-pentenyl!-(3a(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborole was dissolved in 2 ml of tetrahydrofuran and then cooled to -78° C. under a nitrogen atmosphere. 0.56 ml (0.56 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran was added dropwise. The solution was then stirred overnight while slowly warming to room temperature. The solvent was removed by evaporation and the residue was taken up in diethyl ether. Insoluble material was removed by filtration. The solvent was removed by evaporation, the residue was dissolved in 2 ml of diethyl ether and the solution was cooled to 0° C. 0.12 ml (1.7 mmol) of trifluoroacetic acid was added and the solution was stirred at 0° C. for 30 minutes. The solution was evaporated and the residue was co-evaporated with toluene to give 0.0226 g of α-(R)-(3-butenyl)-3a(S),4(S),5,6(S),7, 7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborole-2-methylamine trifluoroacetate (1:1) as an oil which was used in the next step without further purification.

iii) 0.35 g (0.38 mmol) of N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine was dissolved in 2 ml of dimethylformamide and 6 ml of dichloromethane. 0.21 ml (1.9 mmol) of N-methylmorpholine was added and the solution was cooled to -15° C. under a nitrogen atmosphere. 66 mg (0.46 mmol) ofisobutyl chloroformate were added and the solution was stirred for 10 minutes at -15° C. 0.2 g (0.53 mmol) of α-(R)-(3-butenyl)-3a(S),4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzoxaborole-2-methylamine trifluoroacetate (1.1) wasadded and the mixture was stirred at room temperature for 5 hours. The solution was diluted with dichloromethane, washed with 2M hydrochloric acid and water and dried over anhydrous sodium sulphate. After evaporationthe residue was triturated with diethyl ether and dried. There was obtained0.309 g of N2- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(3a(S),4(S),5,6(S),7,7a(S)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)-4-pentenyl-L-leucinamide as as solid which was used without further purification.

iv) 300 mg (0.26 mmol) of N2- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl-3-methyl-L-valyl!-N1-1(R)-(3a(S),4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)-4-pentenyl!-L-leucinamide were dissolved in 3.5 ml of trifluoroacetic acid and 3.5 ml of dichloromethane. The solution was stirred at room temperature for 45 minutes, then diluted with toluene and evaporated. The residue was triturated with diethyl ether and the resulting solid was filtered off and dried and then purified by chromatography on silica gel using dichlomethane/methanol/acetic acid/water (170:15:3:2) for the elution. There were obtained 135 mg of N2- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(3a(S), 4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)-4-pentenyl!-L-leucinamide as a white solid: MS: m/e 995.3 M+H!⁺.

EXAMPLE 22

N2- N- N- N- N-(3-Carboxypropionyl)-L-α-aspartyl!-L-α-gluatamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(3a(S),4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)propyl!-L-leucinamide can be converted into 1(R)- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!propylboronic acid in a manner analogous to that described in the first paragraph of Example 20.

The starting material was prepared as follows:

i ) In an analogous manner to that described in Example 21 i) and ii), by replacing 3-butenylmagnesium bromide with ethylmagnesium bromide there wasobtained α(R)-ethyl-3a(R)-ethyl-3a(S),4,(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborole-2-methylamine trifluoroacetate (1:1) which was used in the next step without further purification.

ii) 0.35 g (0.38 mmol) of N- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl-3-methyl-L-valyl!-L-valyl!-L-leucine was dissolved in 3 ml of dimethylformamide and 7 ml of dichloromethane. 0.2 ml (1.9 mmol) of N-methylmorpholine was added and thesolution was cooled to -10° C. under a nitrogen atmosphere. 68 mg (0.53 mmol) of isobutyl chloroformate were added and the solution was stirred for 10 minutes at -10° C. 0.18 g (0.53 mmol) of a(R)-ethyl-3a(S)4(S),5,6,(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborole-2-methylamine trifluoroacetate (1:1) was added andthe mixture was stirred at room temperature for 16 hours. After evaporationthe residue was partitioned between ethyl acetate and 2M hydrochloric acid.The organic layer was washed with water and saturated sodium chloride solution and then dried over anhydrous sodium sulphate. The solution was evaporated and the residue was trituated with diethyl ether, filtered off and dried to give 0.22 g of N2- N- N- N- N- 3-(tert-butoxycarbonyl)-propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(3a(S),4(S),5,6(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)propyl!-L-leucinamide as a solid which was used without further purification.

ii) 0.22 g (0.19 mmol) of N2- N- N- N- N- 3-(tert-butoxyarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-lutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-3a(S),4(S),5,6,(S),7,7a(R)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)propyl!-L-leucinamide was dissolved in 5ml of trifluoroacetic acid and 5 ml of dichloromethane, the solution was stirred at room temperature for 1 hour and then diluted with toluene and evaporated. The residue was triturated with diethyl ether and the resulting solid was filtered off and dried to give 170 mg of N2- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-gluatamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(R)-(3a(S),4(S),5,6(S),7,7a(R)-hexahydro-3a, 5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl)propyl!-L-leucinamideas a white solid; MS: m/e 969.4 M+H!⁺.

EXAMPLE 23

4 g of 0.25 mmol/g 5- 2- 1(RS)- N- (9-fluorenyl)methoxycarbonyl!-L-leucyl!amino!propyl!-4(RS),5,5-trimethyl-1,3,2-dioxoborolan-4-yl!-3(RS)-methyl-N- α(RS)-(4-methylphenyl)benzyl!valeramide-polystyrene conjugate were swollen in dimethylformamide for 20 minutes and then suspended and agitated in dimethylformamide/piperidine (4.1). After 5 minutes the resin was drained and then suspended in and agitated with dimethylformamide/piperidine (4.1)for a further 5 minutes. The resin was then drained and washed five times with dimethylformamide.

The resin was then suspended in a solution of 2.1 g (6 mmol) of N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-valine in dimethylformamide and then a mixture of 1.9 g of 2-(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 1.3 ml of N-methylmorpholine dissolved in dimethylformamide was added. After agitating for 40 minutes the resin was drained and washed five times with dimethylformamide.

The resin was resuspended in and agitated with dimethylformamide/piperidine(4:1). After 5 minutes the resin was drained and resuspended in and agitated with dimethylformamide/ piperidine (4:1) for a further 5 minutes.Then, the residue was drained and washed five times with dimethyl formamide.

The resin was then suspended in a solution of 2.4 g (6 mmol) of N- (9-fluorenyl)methoxycarbonyl!-3-(2-methylphenyl)-L-alanine in dimethylformamide and a mixture of 1.9 g of 2(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 1.3 ml of N-methylmorpholine dissolved in dimethylformamide was added. After agitating for 40 minutes the resin was drained and washed five times with dimethyl formamide.

40 mg of this resin were resuspended in and agitated with 0.7 ml of dimethylformamide/piperidine (4:1). After 5 minutes the resin was drained and resuspended in and agitated with dimethylformamide/piperidine (4:1) for a further 5 minutes. Then, the resin was drained and washed five timeswith dimethylformamide.

The resin was then suspended in 0.5 ml of a 0.2M solution of N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-glutamic acid in dimethyl sulphoxide and then 0.5 ml of a mixture of 0.2M 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 0.4M N-methylmorpholine in dimethylformamide was added. After agitating for 1 hour the resin was drained and washed five times with 1 ml of dimethylformamide.

The resin was resuspended in and agitated with 0.7 ml of dimethylformamide/piperidine (4:1). After 5 minutes the resin was drained and resuspended in and agitated with dimethylformamide/piperidine (4:1) for a further 5 minutes. Then, the resin was drained and washed five timeswith 1 ml of dimethylformamide.

The resin was suspended in 0.5 ml of a solution of N-(9-fluorenylmethoxycarbonyl)-O-tert-butyl-L-tyrosine in dimethyl sulphoxide and 0.5 ml of a mixture of 0.2M 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 0.4M N-methylmorpholine in dimethylformamide was added. After agitating for 1 hour the resin was drained and washed five times with 1 ml of dimethylformamide.

The resin was resuspended in and agitated with 0.7 ml of dimethylformamide/piperidine (4:1). After 5 minutes the resin was drained and resuspended in and agitated with dimethylformamide/piperidine (4:1) for a further 5 minutes. Then, the resin was drained and washed five timeswith 1 ml of dimethylformamide.

The residue was suspended in 0.5 ml of a 0.2M solution of tert-butyl hydrogen succinate in dimethylformamide and then 0.5 ml of 0.2M 2-(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 0.4MN-methylmorpholine dissolved in dimethylformamide was added. After agitating for 1 hour the resin was drained and washed five times with 1 mlof dimethylformamide and then twice with 1 ml of dichloromethane.

0.2 ml of dichloromethane was added to the resin which was then treated with 0.7 ml of trifluoroacetic acid/water (19:1) and agitated for 90 minutes. The resin was then filtered off and washed with 0.7 ml of trifluoroacetic acid/water (19:1). The combined trifluoroacetic acid and water solutions were then evaporated in a vacuum centrifuge and the residue was suspended in acetonitrile/water (1:1) and freeze dried. There were obtained 16.8 mg of 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-tyrosyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!propylboronic acid as a white solid; MS m/e 807.4 M+H-H₂ O!⁺.

The starting material was prepared as follows:

i) 25 ml of isobutylene were condensed at -78°C. and added to a mixture of 19.4 g (114 mmol) of 3(RS),7-dimethyl-6-octenoic acid and 1 ml of concentrated sulphuric acid in 25 ml of dichloromethane. The mixture was stirred for 24 hours under a dry ice condenser. A further 20 ml of isobutylene were added and the mixture was stirred for 24 hours under a dry ice condenser. The mixture was diluted with dichloromethane, washed with saturated sodium bicarbonate solution, dried over anhydrous magnesiumsulphate and evaporated under a vacuum. The resulting oil was purified by chromatography on silica gel using ethyl acetate/hexane (1:9) for the elution. There were obtained 20.8 g of tert-butyl 3(RS),7-dimethyl-6-octenoate as a colourless oil. ¹ H NMR (250 MHz, CDCl₃) δ: 0.9 (d, 3 H), 1.1-1.3 (m, 3 H), 1.4 (s, 9 H), 1.6 (s,3 H), 1.65, (s, 3 H), 1.8-2.2 (br m, 4 H), 5.05, (m, 1 H).

ii) 1.5 g (6.64 mmol) of tert-butyl 3(RS),7-dimethyl-6-octenoate were dissolved in a mixture of 10 ml of acetone, 2 ml of water and 2 ml of glacial acetic acid. 2 g (12.6 mmol) of potassium permanganate were added and the resulting mixture was stirred at 30° C. for 2 hours. 22 ml of 2M sulphuric acid and 0.8 g (11.3 mmol) of sodium nitrite were added and the organic phase was separated. The aqueous phase was extracted with dichloromethane and the combined organic phases were washed with water, dried over magnesium sulphate and evaporated under a vacuum to give 1.55 gof tert-butyl 7-hydroxy-3(RS),7-dimethyl6-oxo-octenoate as a clear oil; MS:m/e 259 M+H!⁺.

iii) 0.25 g (0.97 mmol) of tert-butyl 7-hydroxy-3(RS),7-dimethyl-6-oxo-octenoate was dissolved in 3 ml of diethyl ether at 0° C. under a nitrogen atmosphere. 0.36 ml (1.1 mmol) of 3M methylmagnesium bromide in diethyl ether was added dropwise and the resulting solution was stirred at 0° C. for 2 hours, refluxed for 6 hours and then stirred at room temperature for 16 hours. The solution was diluted with ethyl acetate and then extracted with 2M hydrochloric acid and saturated sodium chloride solution. The organic phase was dried over anhydrous sodium sulphate and evaporated under a vacuum. The resulting oil was purified by chromatography on silica gel using ethyl acetate/hexane (1:2) for the elution. There were obtained 118 mg of tert-butyl 6(RS),7-dihydroxy-3(RS),6,7-trimethyl-6-octenoate as a clear oil; MS: m/e 275 M+H!⁺.

iv) 0.64 g (2.3 mmol) of tert-butyl 6(RS),7-dihydroxy-3-(RS), 6,7-trimethyl-6-octenoate was stirred in 3 ml of tetrahydrofuran with 0.5 g (2.5 mmol) of dichloromethyl diisopropoxyborane at room temperature for 16 hours. The resulting mixture was evaporated and the residue was co-evaporated with toluene to give 0.86 g of tert-butyl 5- 2-(dichloromethyl)-4(RS),5,5-trimethyl-1,3,2-dioxaborolan-4-yl!-3(RS)-methylvalerate as an oil which was used in the next step without further purification.

v) 0.86 g (2.3 mmol) of tert-butyl 5- 2-(dichloromethyl)-4(RS), 5,5-trimethyl-1,3,2-dioxaborolan-4-yl!-3(RS)-methylvalerate was dissolved in 5 ml of tetrahydrofuran and the solution was cooled to -78° C. under a nitrogen atmosphere. 2.6 ml (2.6 mmol) of 1 M ethylmagnesium bromide in tetrahydrofuran were added dropwise, the resulting solution wasstirred for 16 hours while slowly warming to room temperature and then diluted with ethyl acetate and extracted with 2M hydrochloric acid and brine. The organic phase was dried over sodium sulphate and then evporatedunder a vacuum to give 0.83 g of tert-butyl 5- 2-(1(RS)-chloropropyl)-4(RS),5,5-trimethyl-1,3,2-dioxaborolan-4-yl!-3(RS)-methylvalerate as an oil which was used in the next step without purification.

vi) 0.82 g (2.27 mmol) of tert-butyl 5- 2-(1(RS)-chloropropyl)-4(RS),5,5-trimethyl-1,3,2-dioxaborolan-4-yl!-3(RS)-methylvalerate was dissolved in 10 ml of tetrahydrofuran and then cooledto -78° C. under a nitrogen atmosphere. 2.3 ml (2.3 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise. The solution was then stirred overnight while slowly warming to room temperature. The solvent was removed by evaporation and the residue was taken up in diethyl ether. Insoluble material was removed by filtration and the filtrate was cooled to 0° C. 0.52 ml (6.8 mmol) of trifluoroacetic acid was added and the solution was stirred at 0° C. for 30 minutes. The solution was evaporated and the residue was co-evaporated with toluene to give 1 g of tert-butyl 5- 2-(1(RS)-aminopropyl)-4(RS), 5,5-trimethyl-1,3,2-dioxaborolan-4-yl!-3(RS)-methylvalerate as an oil which was used in the next step without purification.

vii) 0.5 g (1.42 mmol) of N- (9-fluorenyl)methoxycarbonyl!-L-leucine was dissolved in 7 ml of dichloromethane. 0.6 ml (5.7 mmol) of N-methylmorpholine was added and the solution was cooled to -10° C.under a nitrogen atmosphere. 0.22 ml (1.7 mmol) of isobutyl chloroformate was added and the solution was stirred for 7 minutes at -10° C. 1 g(2.13 mmol) of tert-butyl 5- 2-(1(RS)-aminopropyl)-4(RS),5,5-trimethyl-1,3,2-dioxaborolan-4-yl!-3(RS)-methylvalerate was added and the mixture was stirred at room temperature for 16 hours, then diluted with dichloromethane and extracted with 2M hydrochloric acid. The organic phase was extracted with 2M hydrochloric acid and saturated sodium hydrogen carbonate solution and then dried over anhydrous magnesium sulphate. After evaporation the residue was purified by chromatography on silica gel using ethyl acetate/hexane (1:2) for the elution. There was obtained 0.56 g of tert-butyl 5- 2- 1(RS)- N- (9-fluorenyl)methoxycarbonyl!-L-leucyl!amino!propyl!-4(RS),5,5-trimethyl-1,3,2-dioxaborolan-4-yl!-3(RS)-methylvalerate as an oil; MS: m/e 677 M+H!⁺.

viii) 50 mg (0.074 mmol) of tert-butyl 5- 2- 1(RS)- N- (9-fluorenyl)methoxycarbonyl!-L-leucyl!amino!propyl!-4(RS) ,5,5-trimethyl- 1,3,2-dioxaborolan-4-yl!-3(RS)-methylvalerate were dissolved in 1 ml of trifluoroacetic acid and 1 ml of dichloromethane. Thesolution was stirred at room temperature for 15 minutes and then evaporatedunder a vacuum. The residue was co-evaporated with toluene to give 46 mg of5- 2- 1(RS)- N- (9-fluorenyl)methoxycarbonyl!-L-leucyl!amino!propyl!-4(RS),5,5-trimethyl-1,3,2-dioxaborolan-4-yI!-3(RS)-methylvaleric acid as an oil;MS: m/e 621 M+H!⁺.

ix) 5 g (5.25 mmol) of 4-methylbenzhydrylamine resin were swollen in dimethylformamide and excess solvent was drained from the resin. The resinwas then resuspended in dimethylformamide containing 3.4 g (5.48 mmol) of 5- 2- 1(RS)- N- (9-fluorenyl)methoxycarbonyl!-L-leucyl!amino!propyl!-4(RS),5,5-trimethyl-1,3,2-dioxaborolan-4-yl!-3(RS)-methylvaleric acid and 3 g (8.2 mmol) of 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate. Thereto there were added 3.0 ml (16.5 mmol) of diisopropylamine. The resulting mixture was agitated for 100 minutes and the resin was then drained and washed three times with dimethylformamide. The resin was then resuspended in dimethylformamide containing 5 ml (54.8 mmol) of acetic anhydride and 11.5 ml (110 mmol) of N-methylmorpholine. The mixture was agitated for 30 minutes and the resin was then drained. The resin was then resuspended in dimethylformamide containing 5 ml (54.8 mmol) of acetic anhydride and 11.5 ml (110 mmol) of N-methylmorpholine. The mixture was agitated for 30 minutes and the resin was then drained andwashed three times with dimethylformamide, twice with ethyl acetate, twice with dichloromethane and twice with diethyl ether and then dried under a vacuum. After drying there was obtained 6 g of 5- 2- 1(RS)- N- (9-fluorenyl)methoxycarbonyl!-L-leucyl!amino!propyl! -4-(RS),5,5-trimethyl-1,3,2-dioxoborolan-4-yl!-3(RS)-methyl-N- α(RS)-(4-methylphenyl)benzyl!valeramide-polystyrene conjugate as a pale brown solid (0.25 mmol/g loading estimated by quantitation of dibenzofulvene at 301 nM).

EXAMPLE 24

In an analogous manner to that described in Example 5, from N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl!-L-alaninamide there was obtained 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanyl!amino!-3-butenylboronic acid as a white solid; MS: m/e 855 M+H-H₂ O!.

The starting material was prepared as follows:

i) A mixture of 1.2 g (4.67 mmol) of N-(tert-butoxycarbonyl)-3-cyclopentyl-L-alanine, 540 mg (5 mmol) of benzylalcohol, 675 mg (5 mmol) of 1-hydroxybenzotriazole, 1.152 g (6 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.031 g (0.25 mmol) of 4-dimethylaminopyridine was stirred in 20 ml of dichloromethane for 1 hour and then a further 610 mg (5 mmol) of 4-dimethylaminopyridine were added. After 4 hours the solution was extracted with 2M hydrochloric acid and saturated sodium bicarbonate solution, dried over anhydrous magnesium sulphate and evaporated. The oil obtained was chromatographed on silica gel using ethyl acetate/ petrol (1:6) for the elution to give 1.55 g of N-(tert-butoxycarbonyl)-3-cyclopentyl-L-alanine benzyl ester as a colourless oil; MS: m/e 348 M+H!.

ii) 1.54 g (4.44 mmol) of N-(tert-butoxycarbonyl)-3-cyclopentyl-L-alanine benzyl ester and 2.53 g (13.32 mmol) of 4-toluenesulphonic acid hydrate were dissolved in 20 ml of acetonitrile and the solution was left to standat room temperature for 18 hours. The white precipitate formed was filteredoff and added to a mixture of 867 mg (3.75 mmol) of N-(tert-butoxycarbonyl)-3-methyl-L-valine, 557 mg (3.64 mmol) of 1-hydroxybenzotriazole, 793 mg (4.14 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 475 mg (4.13 mmol) of N-ethylmorpholine in 25 ml of dichloromethane and stirred at room temperature for 18 hours. The solution was extracted with 2M hydrochloric acid and saturated sodium bicarbonate solution and then driedover anhydrous magnesium sulphate. Evaporation and chromatography on silicagel using ethyl acetate/petrol (1:3) for the elution gave 1.06 g of N- N-(tert-butoxycarbonyl)-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester as an off-white foam; MS: m/e 461 M+H!.

iii) 993 mg (2.16 mmol) of N- N-(tert-butoxycarbonyl)-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester and 1.23 g (6.47 mmol) of 4-toluenesulphonic acid hydrate were dissolved in 20 ml of acetonitrile and the solution was stirred at room temperature for 2 hours. The solvent was removed by evaporation and the residue was triturated with diethyl ether and filtered off. The solid obtained was added to a mixture of 602 mg (2.16 mmol) of N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanine, 338 mg (2.21 mmol) of 1-hydroxybenzotriazole, 576 mg (3 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 345 mg (3 mmol) of N-ethylmorpholine in 20 ml of dichloromethane and stirred at roomtemperature for 18 hours. The solution was extracted with 2M hydrochloric acid and saturated sodium bicarbonate solution, then dried over anhydrous magnesium sulphate and evaporated. Chromatography of the residue on silicagel using ethyl acetate/ petrol (3:7) for the elution gave 990 mg of N- N- N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester as a white solid; MS: m/e 622 M+H!.

iv) 980 mg (1.578 mmol) of N- N- N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester and 900 mg (4.73 mmol) of 4-toluenesulphonic acid hydrate were dissolved in 16 ml of acetonitrile and the solution was stirred at room temperature for 2 hours. The solvent was removed by evaporation and the residue was triturated with diethyl ether and filtered off. The solid obtained was added to a mixture of 671 mg (1.578 mmol) of N-(9-fluorenylmethoxycarbonyl)-O-tert-butyl-L-α-glutamic acid, 247 mg (1.614 mmol) of 1-hydroxybenzotriazole, 419 mg (2.19 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 252 mg (2.19 mmol) of N-ethylmorpholine in 16 ml of dichloromethane and stirred at room temperature for 18 hours. The solution was extracted with 2M hydrochloric acid and saturated sodium bicarbonate solution and then driedover anhydrous magnesium sulphate. Evaporation and chromatography on silicagel using methanol/dichloromethane (1:49) for the elution gave 530 mg of N- N- N- O-tert-butyl-N-(9-fluorenylmethoxycarbonyl)-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester as a white solid; MS: m/e 929 M+H!.

v) A solution of 520 mg (0.56 mmol) of N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester in 3 ml of piperidine and 12 ml of dichloromethane was stirred at room temperature for 30 minutes. The solvent was removed by evaporation and the residue was chromatographed on silica gel using firstly ethyl acetate/petrol (1:1) and then methanol/dichloromethane (1:9) for the elution. The resulting amine was added to a solution of 207 mg (0.504 mmol) of N-(9-fluorenylmethoxycarbonyl)-O-tert-butyl-L-α-aspartic acid, 78 mg (0.51 mmol) of 1-hydroxybenzotriazole and 134 mg (0.7 mmol) of1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 10 ml of dichloromethane and stirred at room temperature for 18 hours. The solutionwas then extracted with 2M hydrochloric acid and saturated sodium bicarbonate solution and dried over anhydrous magnesium sulphate. Evaporation, trituration with diethyl ether and filtration gave 440 mg of N- N- N- N-O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester as a white solid; MS: m/e 1101 M+H!.

vi) A solution of 430 mg (0.39 mmol) of N- N- N- N-O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester in 4 ml of piperidine and 16 ml ofdichloromethane was stirred at room temperature for 30 minutes and then evaporated. The residue was chromatographed on silica gel using firstly ethyl acetate/petrol (1:1) and then methanol/dichloromethane (1:9) for theelution. The amine obtained was added to a solution of 174 mg (1 mmol) of tert-butyl hydrogen succinate, 135 mg (1 mmol) of 1-hydroxybenzotriazole and 192 mg (1 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in 15 ml of dichloromethane and the mixture was stirred at room temperature for 18 hours, extracted with 2M hydrochloric acid and saturated sodium bicarbonate solution and then dried over anhydrous magnesium sulphate. Evaporation and chromatography on silica gel using methanol/dichloromethane (1:24) for the elution followed by trituration with diethyl ether gave 240 mg of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester as a white solid; MS: m/e 1035 M+H!.

vii) A solution of 230 mg (0.223 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine benzyl ester in 10 ml of dimethylformamidewas hydrogenated over 25 mg of 10% palladium/carbon for 3 hours. The catalyst was removed by filtration, the filtrate was evaporated and the residue was triturated with diethyl ether to give 206 mg of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine as a white solid; MS: m/e 944 M+H!.

viii) 163 mg (0.173 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-L-alanine were dissolved in 2 ml of dimethylformamide and 4 ml of dichloromethane. 80 mg (0.69 mmol) of N-ethylmorpholine were added and the solution was cooled to -10° C.26 mg (0.19 mmol) of isobutyl chloroformate were added and the solution wasstirred for 30 minutes at -10° C. 107 mg (0.345 mmol) of α-(RS)-allyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate in 1 ml of dichloromethane were added and the mixture wasstirred at -10° C. for 30 minutes and at room temperature for 3 hours. The solution was extracted with 2M hydrochloric acid and saturated sodium bicarbonate solution and then dried over anhydrous magnesium sulphate. Evaporation and chromatography on silica gel using methanol/dichloromethane (1:24) for the elution gave 54 mg of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cyclopentyl-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl!-L-alaninamide as a white solid; MS: m/e 1024 M+H-C₆ H₁₂ O!.

EXAMPLE 25

In an analogous manner to that described in Example 5, from N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-cyclohexyl-L-alanyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl-L-leucinamide, MS: m/e 1037 M+H-C₆ H₁₂ O!, there was obtained 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-cyclohexyl-L-alanyl!-L-leucyl!amino!-3-butenylboronic acid; MS: m/e 869 M+H-H₂ O!.

The starting material was prepared in an analogous manner to that describedin Example 5 via the following intermediates:

i) N- N-(tert-Butoxycarbonyl)-3-cyclohexyl-L-alanyl!-L-leucine benzyl ester; MS: m/e 475 M+H!;

ii) N- N- N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanyl!-3-cyclohexyl-L-alanyl!-L-leucine benzyl ester; MS: m/e 636 M+H!;

iii) N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-cyclohexyl-L-alanyl!-L-leucine benzyl ester; MS: m/e 944 M+H!;

iv) N- N- N- N - O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-cyclohexyl-L-alanyl!-L-leucine benzyl ester; MS: m/e 1114 M+H!;

v) N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-cyclohexyl-L-alanyl!-L-leucine benzyl ester; MS: m/e 1049 M+H!; and

vi) N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-cyclohexyl-L-alanyl!-L-leucine; MS: m/e 958 M+H!.

EXAMPLE 26

In an analogous manner to that described in Example 5, from N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-phenylglycyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl-L-leucinamide, MS: m/e 1017 M+H-C₆ H₁₂ O!, there was obtained 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-phenylglycyl!-L-leucyl!amino!-3-butenylboronic acid; MS: m/e 849 M+H-H₂ O!.

The starting material was prepared in an analogous manner to that describedin Example 5 via the following intermediates:

i ) N- N-(tert-Butoxycarbonyl)-L-2-phenylglycyl!-L-leucine benzyl ester; MS: m/e 455 M+H!;

ii) N- N- N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanyl!-L-2-phenylglycyl!-L-leucine benzyl ester; MS: m/e 616 M+H!;

iii) N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-phenylglycyl!-L-leucine benzyl ester; MS: m/e923 M+H!;

iv) N- N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-phenylglycyl!-L-leucine benzyl ester; MS: m/e 1094 M+H!;

v) N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl -L-phenylalanyl!-L-2-phenylglycyl!-L-leucine benzyl ester; MS: m/e 1028 M+H!; and

vi) N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-phenylglycyl!-L-leucine; MS: m/e 938 M+H!.

EXAMPLE 27

In an analogous manner to that described in Example 5, from N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-N 1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl-L-leucinamide, MS: m/e 1023 M+H-C₆ H₁₂ O!, there was obtained 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucyl!amino!-3-butenylboronic acid; MS: m/e 855 M+H-H₂ O!.

The starting material was prepared in an analogous manner to that describedin Example 5 via the following intermediates:

i) N- N-(tert-Butoxycarbonyl)-L-2-cyclohexylglycyl!-L-leucine benzyl ester;MS: m/e 461 M+H!;

ii) N- N- N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucine benzyl ester; MS: m/e 622 M+H!;

iii) N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucine benzyl ester; MS:m/e 929 M+H!;

iv) N- N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucine benzyl ester; MS: m/e 1100 M+H!;

v) N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl- L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucine benzyl ester; MS: m/e 1034 M+H!; and

vi) N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucine; MS: m/e 944 M+H!.

EXAMPLE 28

In an analogous manner to that described in Example 5, from N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl-L-prolinamide, MS: m/e 981 M+H-C₆ H₁₂ O!, there was obtained 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-prolyl!amino!-3-butenylboronic acid as a white solid; MS: m/e 813 M+H-H₂ O!.

The starting material was prepared in an analogous manner to that describedin Example 5 via the following intermediates:

i) N- N-(tert-Butoxycarbonyl)-3-methyl-L-valyl!-L-proline benzyl ester;

ii) N- N- N-(tert-butoxycarbonyl)-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-proline benzyl ester;

iii) N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-proline benzyl ester;

iv) N- N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-proline benzyl ester;

v) N- N- N- N- O-tert-butyl-N- 3-(tert-butoxycarbonyl)-propionyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl-L-proline benzyl ester; MS: m/e 992 M+H!; and

vi) N- N- N- N- -O-tert-butyl-N- 3-(tert-butoxycarbonyl)-propionyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl-2-methyl-L-phenylalanyl!-3-methyl-L-valyl-L-proline.

EXAMPLE 29

In an analogous manner to that described in Example 5, from N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-phenylalanyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl-L-leucinamide, MS: m/e 1031 M+H-C₆ H₁₂ O!, there was obtained 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylaianyl!-L-phenylalanyl!-L-leucyl!amino!-3-butenylboronic acid as a white solid; MS: m/e 863 M+H-H₂ O!.

The starting material was prepared in an analogous manner to that describedin Example 5 via the following intermediates:

i) N- N- N- O-tert-Butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-phenylalanyl!-L-leucine benzyl ester;

ii) N- N- N- N- O-tert-butyl-N- (9-fluorenyl)methoxycarbonyl!-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-phenylalanyl!-L-leucine benzyl ester;

iii) N- N- N- N-N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-phenylalanyl!-L-leucine benzyl ester; MS m/e 1042 M+H!; and

iv) N- N- N- N-N- 3-(tert-butoxycarbonyl)propionyl!-3-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-phenylalanyl!-L-leucine.

Example 30

0.04 g (0.03 mmol) of (E)-N2- N- N- N- N-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-pentyl!-L-leucinamide was dissolved in 4 ml of a 1:1 solution of dichloromethane and trifluoroacetic acid containing 3 drops of water. The resulting solution was stirred at room temperature for 1 hour. After removal of the solvent by evaporation and trituration of the residue with diethyl ether there was obtained 0.014 g of (E)-2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-.alpha.-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-hexenal; MS: m/e 845.7 M+H!⁺.

The starting material was prepared as follows:

i) 25 g (347 mmol) of trans-2-buten-1-ol were dissolved in 750 ml of anhydrous diethyl ether. 7.25 ml (89.63 mmol) of anhydrous pyridine were added and the resulting solution was cooled to 0° C. 88.25 ml of phosphorus tribromide were added dropwise and the mixture was stirred for 2 hours at 0° C. The reaction was quenched by pouring the solution on to ice. The organic phase was washed with saturated sodium chloride solution and dried over anhydrous magnesium sulphate. After removal of thesolvent by evaporation there was obtained (E)-1-bromo-2-butane which was used in the next step without purification.

ii) 3.86 g (168 mmol) of sodium metal were dissolved in 106 ml of anhydrousethanol. 36.35 g (168 mmol) of diethyl acetamidomalonate dissolved in 225 ml of anhydrous ethanol were added and the mixture was heated under refluxfor 10 minutes. 22.66 g (168 mmol) of (E)-1-bromo-2-butene were added dropwise at room temperature and the mixture was stirred overnight and then evaporated to dryness under a vacuum. The residue was partitioned between ethyl acetate and 0.1M hydrochloric acid. The organic phase was washed with saturated sodium hydrogen carbonate solution and then with saturated sodium chloride solution and dried over anhydrous magnesium sulphate. The solvent was evaporated to give 40 g of diethyl (E)-2-acetamido-2-(2-butenyl)malonate as a colourless oil; ¹ H NMR (250 MHz, CDCl₃) δ: 1.25 (t, 6 H), 1.6 (d, 3 H), 2.0 (s, 3 H), 2.9 (d, 2 H), 4.2 (q, 4 H), 5.15 (m, 1 H) 5.5 (m, 1 H), 6.7 s, 1 H).

iii) 39.63 g (146 mmol) of diethyl (E)-2-acetamido-2-(2-butenyl)malonate were dissolved in 200 ml of ethanol and a solution of 19.24 g (481 mmol) of sodium hydroxide in 100 ml of water was added. The mixture was stirred for 2 hours at 60° C., evaporated to dryness under a vacuum and theresidue was partitioned between diethyl ether and water. The aqueous phase was acidified with 2M hydrochloric acid and extracted with ethyl acetate. The organic phase was dried over magnesium sulphate and the solvent was removed by evaporation under a vacuum to give 26.1 g of (E)-2-acetamido-2-(2-butenyl)malonic acid as a white solid which was used in the next step without further purification. 1 H NMR (250 MHz, MeOD) δ: 1.65 (d, 3 H), 2.0 (s, 3 H), 2.9 (d, 2 H), 5.25 (m, 1 H), 5.5 (m,1 H).

iv) 26.1 g (121 mmol) of (E)-2-acetamido-2-(butenyl)malonic acid were dissolved in 200 ml of toluene. 34 ml (242 mmol) of triethylamine were added and the mixture was heated under reflux for 1 hour. The solution wasextracted with 1M hydrochloric acid and the aqueous layer was extracted with ethyl acetate. The combined organic phases were dried over magnesium sulphate and the solvent was removed under a vacuum to give 18.73 g of (E)-N-acetyl-DL-2-(2-butenyl)glycine as a white solid which was used in the next step without purification. 1 H NMR (250 Hz, MeOD) δ: 1.65 (d, 3 H), 2.0 (s, 3 H), 2.4 (m, 2 H), 4.3 (m, 1 H), 5.4 (m, 1 H), 5.5 (m, 1 H).

v) 9 g (52.63 mmol) of (E)-N-acetyl-DL-2-(2-butenyl)glycine were dissolved in 100 ml of water and the pH adjusted to 7.5 using ammonia solution. 0.09g of acylase I extracted from porcine kidney, and 0.042 g (0.3 mmol) of cobalt (II) chloride were added and the mixture was stirred at 37° C. overnight. A further 0.09 g of acylase I extracted from porcine kidney was added and the pH adjusted to 7.5 using ammonia solution. The mixture was stirred at 37° C. overnight and the solution was then heated at80° C. for 30 minutes and was then acidified to pH 1 using 2M hydrochloric acid. The solvent was removed by evaporation under vacuum andthe crude product purified by trituration using ethyl acetate to yield 4.2 g of (E)-L-2-(2-butenyl)glycine hydrochloride. 1 H NMR (250 MHz, D₂ O) δ: 1.7 (d, 3 H), 2.6 (m, 2 H), 4.0 (m, 1 H), 5.35 (m, 1 H), 5.7 (m, 1 H).

vi) 2.1 g (12.69 mmol) of (E)-L-(2-butenyl)glycine hydrochloride were suspended in 20 ml of water and 20 ml of dioxan. 8.26 g (98.32 mmol) of sodium hydrogen carbonate and 8.15 g (37.33 mmol) of di-tert-butyl dicarbonate were added and the resulting solution was stirred for overnight. The solution was evaporated to dryness under a vacuum and the residue was partitioned between diethyl ether and saturated aqueous sodiumhydrogen carbonate solution. The aqueous phase was acidified with 2M hydrochloric acid while partitioning in ethyl acetate. The organic phase was dried over magnesium sulphate and the solvent was removed by evaporation to give 1.34 g of (E)-N-(tert-butoxycarbonyl)-L-2-(2-butenyl)glycine; ¹ H NMR (250 MHz,CDCl₃) δ: 1.4 (s, 9 H), 1.65 (d, 3 H), 2.5 (m, 2 H), 4.3 (m, 1 H), 5.0 (m, 1 H), 5.35 (m, 1 H), 5.6 (m, 1 H).

vii) 1.34 g (5.85 mmol) of (E)-N-(tert-butoxycarbonyl)-L-2-(2-butenyl)glycine were dissolved in 50 mlof anhydrous tetrahydrofuran and the solution was treated in sequence with 0.80 g (8.20 mmol) of N,O-dimethylhydroxylamine hydrochloride, 1.10 g (7.19 mmol) of 1-hydroxybenzotriazole monohydrate, 1.57 g (8.22 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 4 ml (22.96 mmol) of ethyldiisopropylamine. The solution obtained was stirred at room temperature overnight, then washed with saturated sodium hydrogen carbonate solution and with saturated sodium chloride solution and dried over magnesium sulphate. Removal of the solvent by evaporation yielded 1.56 g of N,O-dimethyl (E)-2(S)-(tert-butoxyformamido)-4-hexenohydroxamateas a colourless oil which was used in the next step without purification. ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s, 9 H), 1.65 (d, 3 H), 2.3 (m, 2 H), 3.15 (s, 3 H), 3.75 (s, 3 H), 4.7 (m, 1 H), 5.1 (d, 1 H), 5.35 (m, 1 H), 5.5 (m, 1 H).

viiii) 1.56 g (5.74 mmol) of N,O-dimethyl (E)-2(S)-(tert-butoxyformamido)-4-hexenohydroxamate were dissolved in 10 ml of anhydrous tetrahydrofuran and cooled to 0° C. 4.0ml of a 1M solution of lithium aluminium hydride in tetrahydrofuran were added and the resulting solution was stirred for 30 minutes. The reaction was quenched by the dropwise addition of saturated potassium hydrogen sulphatesolution followed by diethyl ether. The resulting two-phase system was stirred vigorously for 3 minutes. The organic phase was washed with saturated sodium hydrogen carbonate solution followed by saturated sodium chloride solution and dried over anhydrous magnesium sulphate. After removal of the solvent by evaporation the resulting aldehyde was used without purification.

1 g (4.69 mmol) of the aldehyde was dissolved in a saturated solution of hydrogen chloride in methanol and stirred at room temperature for 2 hours.After removal of the solvent by evaporation the dimethyl acetal obtained was used without purification.

0.15 mg (0.16 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine, 0.033 g (0.22 mmol) of 1-hydroxybenzotriazole monohydrate, 0.047 g (0.25 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.77 g (6.69 mmol) of 4-ethylmorpholine were dissolved in 15 ml of dichloromethane. 0.05 g (0.22 mmol) of the dimethyl acetal dissolved in 5 ml of dichloromethane was added and the resulting solution was stirred at room temperature for 3 days. The mixture was washed with 5% citric acid solution followed by saturated sodium hydrogen carbonate solution and saturated sodium chloride solution and then dried over anhydrous magnesiumsulphate. After evaporation of the solvent the crude product was chromatographed on silica gel using 2% methanol in dichloromethane for theelution to give 0.079 g of (E)-N2- N- N- N- N-(3-tert-butoxycarbonyl)propionyl!-tert-butyl-L-α-aspartyl!-O-tert-butyl-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(S)-(dimethoxymethyl)-3-pentyl!-L-leucinamide as a white solid foam; m/e 1027.9 M+H-MeOH!⁺.

EXAMPLE 31

0.05 g (0.04 mmol) of (Z)-N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-.alpha.-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(S)-(dimethoxymethyl)-3-pentenyl!-L-leucinamide was dissolved in 4 ml of a 1:1 solution of dichloromethane and trifluoroaceticacid and containing 3 drops of water. The solution was stirred at room temperature for 1 hour. After removal of the solvent by evaporation the crude product was triturated using diethyl ether to afford 0.03 g of (Z)-2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-alpha-aspartyl!-L-alpha-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-hexenal as a white solid; MS: m/e 845.7 M+H!⁺.

The starting material was prepared as follows:

i) 25 g (347 mmol) of cis-2-buten-1-ol were dissolved in 750 ml of anhydrous diethyl ether. 7.25 ml of anhydrous pyridine were added and the resulting solution cooled to 0° C. 88.25 ml of phosphorus tribromide was added dropwise and the mixture was stirred for 2 hours at 0° C. The reaction was quenched by pouring the solution onto ice. The organic phase was washed with saturated sodium chloride solution and dried over anhydrous magnesium sulphate. After removal of the solvent by evaporation there was obtained 25.65 g of (Z)-1-bromo-2-butene; ¹ H NMR (250 MHz, CDCl₃) δ: 1.65 (d, 3 H), 3.9 (d, 2 H), 5.6 (m, 2 H).

ii) 4.37 g (190 mmol) of sodium metal were dissolved in 110 ml of anhydrousethanol. 41.14 g (189.6 mmol) of diethyl acetamidomalonate dissolved in 270ml of anhydrous ethanol were added and the mixture was heated under reflux for 10 minutes. 25.65 g (168 mmol) of (Z)-1-bromo-2-butene were added dropwise at room temperature and the mixture was stirred overnight, then evaporated to dryness under vacuum and the residue was partitioned betweenethyl acetate and 0.1M hydrochloric acid. The organic phase was washed withsaturated sodium hydrogen carbonate solution followed by saturated sodium chloride solution and dried over anhydrous magnesium sulphate. After removal of the solvent by evaporation the crude product was chromatographed on silica gel using 66% ethyl acetate in petroleum ether as eluent to obtain 44.69 g of diethyl (Z)-2-acetamido-2-(2-butenyl)malonate as a colourless oil;¹ H NMR (250 MHz, CDCl₃) δ:1.2 (t, 6 H), 1.6 (d, 3 H), 2.0 (s, 3 H), 3.1 (d, 2 H), 4.2 (q, 4 H), 5.1(m, 1 H), 5.6 (m, 1 H), 6.7 (s, 1 H).

iii) 44.69 g (165 mmol) of diethyl (Z)-2-acetamido-2-(2-butenyl)malonate were dissolved in 230 ml of ethanol and a solution of 21.69 g (542 mmol) of sodium hydroxide in water was added. The mixture was stirred for 2 hours at 60° C., evaporated to dryness under a vacuum and the residue was partitioned between diethyl ether and water. The aqueous phasewas acidified using 2M hydrochloric acid and extracted with ethyl acetate. The organic phase was dried over magnesium sulphate and the solvent removed by evaporation in a vacuum to give 33.5 g of (Z)-2-acetamido-2-(2-butenyl)malononic acid as a white solid; ¹ H NMR(250 MHz, MeOD) δ: 1.6 (d, 3 H), 2.0 (s, 3 H), 2.85 (d, 2 H), 5.25 (m, 1 H), 5.6 (m, 1 H).

iv) 16.82 g (78.23 mmol) of (Z)-2-acetamido-2-(2-butenyl)-malononic acid were dissolved in 100 ml of toluene. 34 ml (242 mmol) of triethylamine were added and the mixture was heated under reflux for 1 h, then washed with 1M hydrochloric acid and the aqueous phase was extracted with ethyl acetate. The combined organic phases were dried over magnesium sulphate and the solvent was removed under a vacuum to give 9.4 g of (Z)-N-acetyl-DL-2-(2-butenyl)glycine as a white solid; 1 H NMR (250 MHz, MeOD) δ: 1.6 (d, 3 H), 2.0 (s, 3 H), 2.5 (m, 2 H), 4.4 (m, 1 H), 5.4(m, 1 H), 5.6 (m, 1 H).

v) 9.4 g (54.97 mmol) of (Z)-N-acetyl-DL-2-(2-butenyl)glycine were dissolved in 100 ml of water and the pH was adjusted to 7.8 with ammonia solution. 0.09 g of acylase I extracted from porcine kidney, and 0.042 g (0.3 mmol) of cobalt (II) chloride were added and the resulting reaction mixture was stirred at 37° C. overnight. The pH was adjusted to 7.8using ammonia solution. The mixture was stirred at 37° C. overnight and was then heated at 80° C. for minutes and was then acidified topH 1 using 2M hydrochloric acid. The solution was acidified to pH 1 using 2M hydrochloric acid and then heated at 80° C. for 30 minutes. The solvent was removed by evaporation under a vacuum and the crude product obtained purified by trituration using ethyl acetate to yield 5.86 g of (Z)-L-2-(2-butenyl)glycine hydrochloride; ¹ H NMR (250 MHz, D₂ O) δ: 1.6 (d, 3 H), 2.7 (t, 2 H), 4.1 (t, 1 H), 5.3 (m, 1 H), 5.8 (m, 1 H).

vi) 2.9 g (17.52 mmol) of (Z)-L-2-(2-butenyl)glycine hydrochloride were suspended in 25 ml of water and 25 ml of dioxan. 11.4 g (136 mmol) of sodium hydrogencarbonate and 8.49 g (38.94 mmol) of di-tert-butyl dicarbonate were added and the resulting solution was stirred for 48 hours. The solution was evaporated to dryness under a vacuum and the residue was partitioned between diethyl ether and saturated aqueous sodiumhydrogen carbonate solution. The aqueous phase was acidified using 2M hydrochloric acid whilst being partitioned with ethyl acetate. The organicphase was dried over magnesium sulphate and the solvent removed by evaporation to give 2.26 g of (Z)-N-(tert-butoxycarbonyl)-L-2-(2-butenyl)glycine; 1 H NMR (250 MHz, CDCl₃) δ: 1.4 (s, 9 H), 1.6 (d, 3 H), 2.6 (m, 2 H), 4.4 (m, 1 H), 5.05 (m, 1 H), 5.3 (m, 1 H), 5.6 (m, 1 H).

vii) 2.26 g (9.87 mmol) of (Z)-N-(tert-butoxycarbonyl)-L-2-(2-butenyl)glycine were dissolved in 50 mlof anhydrous tetrahydrofuran. 1.15 g (11.79 mmol) of N,O-dimethylhydroxylamine hydrochloride, 1.6 g (10.46 mmol) of 1-hydroxybenzotriazole monohydrate, 2.27 g (11.88 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 5.8 ml of ethyldiisopropylamine were added and the resulting solution was stirred atroom temperature overnight. The solution was washed with saturated sodium hydrogen carbonate solution followed by saturated sodium chloride solutionand then dried over anhydrous magnesium sulphate. Removal of the solvent byevaporation yielded 2.46 g of N,O-dimethyl (Z)-2(S)-(tert-butoxyformamido)-4-hexenohydroxamate as a colourless oil; ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s, 9 H), 1.6 (d, 3 H), 2.35 (m, 1 H), 2.5 (m, 1 H), 3.2 (s, 3 H), 3.75 (s, 3 H), 4.7 (m, 1 H), 5.2 (d, 1 H), 5.35 (m, 1 H), 5.6 (m, 1 H).

viii) 1.01 g (3.71 mmol) of N,O-dimethyl (Z)-2(S)-(tert-butoxyformamido)-4-hexenohydroxamate were dissolved in 10 ml of anhydrous tetrahydrofuran and cooled to 0° C. 2.6 ml of a 1M solution of lithium aluminium hydride in tetrahydrofuran were added and the resulting solution was stirred for 30 minutes. The reaction was quenched by the dropwise addition 15 ml of saturated potassium hydrogen sulphate solution followed by 30 ml of diethyl ether. The resulting two-phase system was stirred vigorously for one hour. The organic phase was washed with saturated sodium hydrogen carbonate solution followed by saturated sodium chloride solution and dried over magnesium sulphate. After removal of the solvent by evaporation the aldehyde was used without further purification. 0.79 g (3.71 mmol) of the aldehyde was dissolved in a saturated solution of hydrogen chloride in 10 ml of methanol and stirredat room temperature for 2 hours. After removal of the solvent by evaporation the dimethylacetal obtained was used without purification.

0.15 g (0.16 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine, 0.033 g (0.22 mmol) of 1-hydroxybenzotriazole mono hydrate, 0.047 g (0.25 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.77 g (6.69 mmol) of 4-ethylmorpholine were dissolved in 15 ml of dichloromethane. 0.05 g (0.22 mmol) of the foregoing dimethyl acetal dissolved in 5 ml of dichloromethane was added and the resulting solution was stirred at room temperature for 3 days. The solution was washed with 5% citric acid solution followed by saturated sodium hydrogen carbonate solution and saturated sodium chloride solution and then dried over magnesium sulphate. After removal of the solvent by evaporation the crude product was chromatographed on silica gel using 2% methanol in dichloromethane for the elution to give 0.092 g of (Z)-N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-.alpha.-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-3-pentenyl!-L-leucinamide, as a white solid foam; MS: m/e 1027.9 M+H-MeOH!⁺.

EXAMPLE 32

In an analogous manner to that described in Example 10, but using N-(tert-butoxycarbonyl)-3-(2-furyl)-L-alanine in place of N-(tert-butoxycarbonyl)-L-allylglycine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-(2-furyl)propionaldehyde; MS: m/e 871.4 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 10 via the following intermediates:

i) N,O-Dimethyl 2(S)-(tert-butoxyformamido)-2-(2-furyl)-propionohydroxamate; ¹ H NMR (250 MHz, CDCl₃) δ: 1.4 (s, 9 H), 3.0 (m, 2 H), 3.2 (s, 3 H), 3.7 (s, 3 H), 4.9 (m, 1 H), 5.3 (br. d, 1 H), 6.1 (br. s, 1 H), 6.3 (br. s, 1 H), 7.3 (br. s, 1 H).

ii) N2-N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 2-(2-furyl)-1(S)-(dimethoxymethyl)ethyl!-L-leucinamide; used directly in the next step.

EXAMPLE 33

In an analogous manner to that described in Example 10, but using N-(tert-butoxycarbonyl)-L-norvaline in place of N-(tert-butoxycarbonyl)-L-allylglycine there was obtained 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!valeraldehyde; MS: m/e 833.4 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 10 via the following intermediates:

N,O-Dimethyl 2(S)-(tert-butoxyformamido)valerohydroxamate; ¹ H NMR (250 MHz, CDCl₃) δ: 0.8 (m, 3 H), 1.2-1.7 (m, 4 H), 1.4 (s, 9 H), 3.1 (s, 3 H), 3.7 (s, 3 H), 4.6 (m, 1 H), 5.1 (br,d, 1 H).

N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)butyl!-L-leucinamide; MS: m/e 1069.6 M+Na!⁺.

EXAMPLE 34

In an analogous manner to that described in Example 10, but using N-(tert-butoxycarbonyl)-L-butylglycine in place of N-(tert-butoxycarbonyl)-L-allylglycine there was obtained 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!hexanal; MS: m/e 847.4 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin example 10 via the following intermediates:

i) N,O-Dimethyl 2(S)-(tert-butoxyformamido)hexanohydroxamate; ¹ H NMR (250 MHz, CDCl₃) δ: 0.9 (m, 3 H), 1.2-1.8 (m, 6 H), 1.4 (s, 9 H), 3.2 (s, 3 H), 3.7 (s, 3 H), 4.6 (m, 1 H), 5.1 (br. d, 1 H).

ii) N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)-pentyl!-L-leucinamide; MS: m/e 1083 M +Na!⁺.

EXAMPLE 35

In an analogous manner to that described in Example 10, but using DL-hexylglycine in place of L-allylglycine hydrochloride there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylaianyl!-3-methyl-L-valyl!-L-leucyl!amino!octanal; MS: m/e 875.5 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 10 via the following intermediates:

i) 2(RS)-(tert-Butoxyformamido)octanoic acid; ¹ H NMR (250 MHz, CDCl₃) δ: 0.9 (m, 3 H), 1.2-1.9 (m, 10 H), 1.4 (s, 9 H), 4.3 (m, 1 H), 5.0 (br. d, 1 H)

ii) N,O-Dimethyl 2(RS)-(tert-butoxyformamido)octanohydroxamate; ¹ H NMR (250 MHz, CDCl₃) δ: 0.9 (m, 3 H), 1.2-1.8 (m, 10 H), 1.4 (s, 9 H), 3.2 (s, 3 H), 3.7 (s, 3 H) 4.6 (m, 1 H), 5.1 (br. d, 1 H)

iii) N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(dimethoxymethyl)-heptyl!-L-leucinamide; MS: m/e 1111.6 M +Na!⁺.

EXAMPLE 36

In an analogous manner to that described in Example 10, but using 2(S)-amino-5-methylhexanoic acid in place of L-allylglycine hydrochloride there was obtained 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-5-methylhexanal; MS: m/e 861.3 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 10 via the following intermediates:

i) 2(S)-(tert-Butoxyformamido)-5-methylhexanoic acid; 1 H NMR (250 MHz, CDCl₃) δ: 0.9 (d, 6 H), 1.2 (m, 2 H), 1.4 (s, 9 H), 1.5 (m, 1 H), 1.7 (m, 1 H), 1.9 (m, 1 H), 4.3 (m, 1 H), 4.9 (br. d, 1 H).

ii) N,O-Dimethyl 2(S)-(tert-butoxyformamido)-5-methylhexanohydroxamate; 1 HNMR (250 MHz, CDCl₃) δ: 0.85 (d, 3 H), 0.9 (d, 3 H), 1.2 (m, 2 H), 1.4 (s, 9 H), 1.4-1.8 (m, 3 H), 3.2 (s, 3 H), 3.8 (s, 3 H), 4.6 (m, 1 H), 5.1 (br. d, 1 H).

iii) N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(S)-(dimethoxymethyl)-4-methylpentyl!-L-leucinamide; MS: m/e 1043.8 M+H-MeOH!⁺.

EXAMPLE 37

In an analogous manner to that described in Example 10, but using 2(S)-amino-5-hexenoic acid in place of L-allylglycine hydrochloride there was obtained 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-5-hexenal; MS: m/e 845.3 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 10 via the following intermediates:

i) 2(S)-tert-Butoxyformamido)-5-hexenoic acid; 1 H NMR (250 MHz, CDCl₃) δ: 1.4 (s, 9 H), 1.8 (m, 1 H), 1.95 (m, 1 H), 2.2 (m, 2 H), 4.3 (m, 1 H), 5.0 (m, 3 H), 5.8 (m, 1 H).

ii) N,O-Dimethyl 2(S)-(tert-butoxyformamido)-5-hexenohydroxamate; 1 H NMR (250 MHz, CDCl₃) δ: 1.4(s, 9 H), 1.6-1.8 (m, 2 H), 2.1 (m, 2 H), 3.2 (s, 3 H), 3.7 (s, 3 H) 4.7 (m, 1 H), 5.0 (m, 3 H), 5.8 (m, 1 H).

iii) N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(S)-(dimethoxymethyl)-4-pentenyl!-L-leucinamide; MS: m/e 1081.6 M +Na!⁺.

EXAMPLE 38

In an analogous manner to that described in Example 10, but using 2(S)-amino-5-hexynoic acid in place of L-allylglycine hydrochloride there was obtained 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-5-hexynal; MS: m/e 843.3 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 10 via the following intermediates:

i) 2(S)-(tert-Butoxyformamido)-5-hexynoic acid; 1 H NMR (250 MHz, MeOD) δ: 1.4 (s, 9 H), 1.8 (m, 1 H), 2.0 (m, 1 H), 2.3 (m, 3 H), 4.2 (m, 1H).

ii) N,O-Dimethyl 2(S)-(tert-butoxyformamido)-5-hexynohydroxamate; 1 H NMR (250 MHz, MeOD) δ: 1.4 (s, 9 H), 1.7 (m, 1 H), 1.9 (m, 1 H), 2.3 (m,3 H), 3.2 (s, 3 H), 3.8 (s, 3 H), 4.7 (m, 1 H).

iii) N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(S)-(dimethoxymethyl)-4-pentynyl!-L-leucinamide; MS: m/e 1079.5 M+Na!⁺.

EXAMPLE 39

In an analogous manner to that described in Example 10, but using N-(tert-butoxycarbonyl)-L-methionine in place of N-(tert-butoxycarbonyl)-L-allylglycine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4-(methylthio)butyraldehyde; MS: m/e 865.3 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 10 via the following intermediates:

i) N,O-Dimethyl 2(S)-(tert-butoxyformamido)-4-(methylthio)butyrohydroxamate; 1 H NMR (250 MHz, CDCl₃) δ: 1.4 (s, 9 H), 1.75 (m, 1 H), 2.0 (m, 1 H), 2.05 (s, 3 H), 2.5 (m, 2 H), 3.2 (s, 3 H), 3.75 (s, 3 H), 4.7 (m, 1 H), 5.2 (m,1 H).

ii) N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(S)-(dimethoxymethyl)-2-(methylthio)propyl!-L-leucinamide; MS: m/e 1047.5 M+H-MeOH!⁺.

EXAMPLE 40

In an analogous manner to that described in Example 10, but using S-(3-phenylpropyl)-L-cysteine in place of L-allylglycine hydrochloride there was obtained 2(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-2- 3-(phenyl)propylthio!propionaldehyde; MS: m/e 955.4 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 10 via the following intermediates:

i) N-(tert-Butoxycarbonyl)-S-(3-phenylpropyl)-L-cysteine; 1 H NMR (250 MHz,CDCl₃) δ: 1.4 (s, 9 H), 1.9 (m, 2 H), 2.55 (t, 2 H), 2.7 (t, 2 H), 3.0 (m, 2 H), 4.5 (m, 1 H), 5.4 (m, 1 H), 7.2 (m, 5 H).

ii) N,O-Dimethyl 2(S)-(tert-butoxyformamido)-3-(3-phenylpropylthio)propionohydroxamate; 1H NMR (250 MHz, CDCl₃) δ: 1.4 (s, 9 H), 1.9 (m, 2 H), 2.5 (t, 2 H), 2.7 (t, 2 H), 2.8 (m, 2 H), 3.2 (s, 3 H), 3.7 (s, 3 H), 4.8 (m, 1 H), 5.3 (m, 1 H), 7.2 (m, 5 H).

iii) N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!3-methyl-L-valyl!-N1- 1(R)-(dimethoxymethyl)-2-(3-phenylpropylthio)ethyl!-L-leucinamide; MS: m/e 1191.8 M+Na!⁺.

EXAMPLE 41

In an analogous manner to that described in Example 1, but sing N,O-Dimethyl 2(S)-(tert-butoxyformamido)hexanohydroxamate in place of N,O-Dimethyl 2(S)-(tert-butoxyformamido)-butyrohydroxamate and N-(9-fluorenylmethoxycarbonyl)-D-valine in place of N-(9-fluorenylmethoxycarbonyl)-O-tert-butyl-L-α-glutamic acid there was obtained 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!hexanal; MS: m/e 817.4 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 1 via the following intermediates:

i) N- N- N- N- (9-Fluorenyl)methoxycarbonyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester; MS: m/e 817.4 M+H!⁺.

ii) N- N- N- N- N- (9-Fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester; MS: m/e 988.4 M+H!⁺.

iii) N- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester; MS: m/e 922.5 M+H!⁺.

iv) N- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine; MS: m/e 832.5 M+H!⁺.

v) N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)pentyl!-L-leucinamide; MS: m/e 997.5 M+Na!⁺.

EXAMPLE 42

In an analogous manner to that described in Example 1, but using N,O-dimethyl 2(S)-(tert-butoxyformamido)hexanohydroxamate in place of N,O-dimethyl 2(S)-(tert-butoxyformamido)-butyrohydroxamate, using N-(9-fluorenylmethoxycarbonyl)-D-valine in place of N-(9-fluorenylmethoxycarbonyl)-O-tert-butyl-L-α-glutamic acid and using O-tert-butyl-N- (9-florenyl)methoxycarbonyl!-L-serine in place of N-(9-fluorenylmethoxycarbonyl)-O-tert-butyl-L-α-aspartic acid there was obtained 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-seryl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!hexanal; MS: m/e 789.3 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 1 via the following intermediates:

i ) N- N- N- N- N- (9-Fluorenyl)methoxycarbonyl!-O-tert-butyl-L-seryl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester; MS: m/e 960.4 M+H!⁺.

ii) N- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-seryl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester; MS: m/e 894.5 M+H!⁺.

iii) N- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-seryl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine; MS: m/e 804.4 M+H!⁺.

iv) N2- N- N- N- N- 3-(tert-Butoxycarbonyl)propionyl!-O-tert-butyl-L-seryl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(S)-(dimethoxymethyl)pentyl!-L-leucinamide; MS: m/e 969.7 M+Na!⁺.

EXAMPLE 43

In an analogous manner to that described in Example 1, but using N,O-dimethyl 2(S)-(tert-butoxyformamido)hexanohydroxamate in place of N,O-dimethyl 2(S)-(tert-butoxyformamido)-butyrohydroxamate using N-(9-fluorenylmethoxycarbonyl)-D-valine in place of N-(9-fluorenylmethoxycarbonyl)-O-tert-butyl-L-α-glutamic acid, usingO-tert-butyl-N- (9-florenyl)methoxycarbonyl!-L-serine in place of N-(9-fluorenylmethoxycarbonyl)-O-tert-butyl-L-α-aspartic acid and using acetic anhydride in place of tert-butyl hydrogen succinate there wasobtained 2(S)- N- N- N- N-(N-acetyl-L-seryl)-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!hexanal; MS: m/e 731.3 M+H!⁺.

The starting material was prepared in an analogous manner to that describedin Example 1 via the following intermediates:

i) N- N- N- N-(N-acetyl-O-tert-butyl-L-seryl)-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine; MS: m/e 690.4 M+H!⁺.

ii) N2- N- N- N-(N-acetyl-O-tert-butyl-L-seryl)-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 1(S)-(dimethoxymethyl)pentyl!-L-leucinamide; MS:m/e 833.5 M+H!⁺.

The reaction with acetic anhydride was carried out as follows:

0.5ml of N-ethylmorpholine and 0.37 ml of acetic anhydride were added in sequence to a solution of 1.95 g of N- N- N- N-(O-tert-butyl-L-seryl)-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester in 70 ml of anhydrous dichloromethane. The mixture was stirred at room temperature for 1 hour and was then washedin sequence with 5% aqueous citric acid solution, saturated aqueous sodium bicarbonate solution and saturated brine. The organic phase was dried overanhydrous magnesium sulphate and evaporated. Chromatography of the residue on silica using 5% methanol in dichloromethane for the elution gave afforded 1.45 g of N- N- N- N-(N-acetyl-O-tert-butyl-L-seryl)-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine benzyl ester; MS: m/e 780.6 M+H!⁺.

EXAMPLE 44

59 mg (0.058 mmol) of N1- 4-bromo-1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)butyl!-N2-N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methylL-phenylalanyl!-3-methyl-L-valyl!-L-leucinamide were dissolved in 3 mlof trifluoroacetic acid and 3 ml of dichloromethane. 5 drops of water were added and the solution was stirred at room temperature for 3 hours. The solution was diluted with toluene and evaporated. The residue was triturated with diethyl ether and the resulting solid was filtered off anddried and then redissolved in 5 ml of trifluoroacetic acid and 5 ml of dichloromethane. The solution was stirred at room temperature for 3 hours and then diluted with toluene and evaporated. The residue was triturated with diethyl ether and the solid obtained was filtered off and dried to give 30 mg of 4-bromo-1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-.alpha.-glutamyl!-2-methylL-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!butylboronic acid in the form of a solid; MS: m/e 911.3 M+H-H₂ O!⁺.

The starting material was prepared as follows:

i) 1.7 ml (1.7 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise to a solution of 0.5 g (1.7 mmol) of 2-(4-bromo-1(RS)-chlorobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (prepared according to EP-A-O 293 881) in ml of tetrahydrofuran under nitrogen at -78° C. The solution was then stirred overnight at roomtemperature. The solvent was removed by evaporation and the residue was taken up in diethyl ether. Insoluble material was removed by filtration and the solvent was removed by evaporation to give 0.63 g of product whichwas immediately redissolved in diethyl ether and cooled to 0° C. 0.34 ml 0.34 ml (5.0 mmol) of trifluoroacetic acid was added and the solution was stirred at 0° C. for 30 minutes. The solution was evaporated and the residue was evaporated with toluene to give 0.58 g of α-(RS)-3-bromopropyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate (1:1) as a brown oil which was used in the next step without purification.

ii) 0.20 g (0.22 mmol) of N- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine was dissolved in 2 ml of dimethylformamide and 6 ml of dichloromethane. 0.2 ml (1.52 mmol) of N-methylmorpholine was added and the solution was cooled to -10° C. under a nitrogen atmosphere. 44 mg (0.3 mmol) of isobutyl chloroformate were added and the solution was stirred for minutes at -10° C. 0.3 g (0.66 mmol) of a(RS)-3-bromopropyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate (1:1) was added and the mixture was stirred at room temperature for 5 hours. Dichloromethane was added and the solution was extracted with 2M hyrochloric acid and water and then dried over anhydroussodium sulphate. After evaporation there was obtained 0.122 g of N2- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-methyl-L-valyl!-N1- 4-bromo-1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl!-L-leucinamide in the form of a solid; MS: m/e 1079.5 M+H-100!⁺.

iii) 115 mg (0.098 mmol) of N2- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 4-bromo-1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl!-L-leucinamide were dissolved in 3 ml of trifluoroacetic acid and 3 ml of dichloromethane. 5 drops of water were added and the solution was stirred at room temperature for 3 hours. The solution was diluted with toluene andevaporated. The residue was triturated with ether and the resulting solid was filtered off and dried to give 72 mg of N1- 4-bromo-1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)butyl!-N2-N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-methyl-valyl!-L-leucinamide as a white solid; MS: m/e 911.3 M+H-100!⁺.

EXAMPLE 45

In an analogous manner to that described in Example 23, but replacing N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-tyrosine with N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-aspartic acid and replacing N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-valine with N- (9-fluorenyl)methoxycarbonyl!-L-2-cyclohexylglycine there was obtained 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methylL-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucyl!amino!propylboronic acid as a white solid; MS: m/e 843.4 M+H-H₂ O!+.

EXAMPLE 46

In an analogous manner to that described in Example 23, but replacing N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-tyrosine with N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-aspartic acid and replacing N- (9-fluorenyl)methoxycarbonyl-2-methyl-L-phenylalanine with N- (9-fluorenyl)methoxycarbonyl!-L-2-cyclohexylglycine there was obtained 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-L-2-cyclohexylglycyl!-3-methyl-L-valyl!-L-leucyllamino!propylboronic acid as a white solid; MS: m/e 795.5 M+H-H₂ O!⁺.

EXAMPLE 47

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-3-cyclohexyl-L-alanine there was obtained2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-3-cyclohexyl-L-alanyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS m/e 897.6 M+H!.

EXAMPLE 48

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-D-valine and replacing N- (9-fluorenyl)methoxycarbonyl!-O-t-butyl-L-α-aspartic acid with N- (9-fluorenyl)methoxycarbonyl!-O-t-butyl-L-serine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-seryl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 815.5 M+H!.

EXAMPLE 49

In an analogous manner to Example 4, by replacing N- (9-flurenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with (9-fluorenyl)methoxycarbonyl!-D-norleucine there was obtained 2(RS)- N- N- N- N- N-(3-carbonylpropionyl)-L-α-aspartyl!-D-norleucyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid;MS: m/e 857.4 M+H!.

EXAMPLE 50

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-D-norvaline there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-norvalyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!-amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 843.4 M+H!.

Example 51

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-D-2-cyclohexylglycine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-2-cyclohexylglycyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid, MS: m/e 897.4 M+H!.

EXAMPLE 52

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-4-nitro-D-phenylalanine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-4-nitro-D-phenylalanyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 936.3 M+H!.

EXAMPLE 53

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-valine with N- (9-fluorenyl)methoxycarbonyl!-L-2-cyclohexylglycine and by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-glutamic acid there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 899.5 M+H!.

EXAMPLE 54

In an analogous manner to Example 4, by replacing N- (9-methoxycarbonyl!-3-(2-methylphenyl)-L-alanine with N- (9-methoxycarbonyl!-L-2-cyclohexylglycine and by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-O-t-butyl-L-α-glutamic acid there was obtained 2(RS)- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-L-2-cyclohexylglycyl!-3-methyl-L-valyl!-L-leucyl!-amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 851.4 M+H!.

EXAMPLE 55

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-O-t-butyl-L-α-glutamic acid and by replacing tert-butyl hydrogen succinate with 3-acetamidobenzoic acid therewas obtained 2(RS)- N- N- N- N- N-(3-acetamidobenzoyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino-4,4,4-trifluororbutyraldehyde as a white solid; MS: m/e 934.4 M+H!.

EXAMPLE 56

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-O-t-butyl-L-α-glutamic acid and by replacing tert-butyl hydrogen succinate with 4-acetamido-3-nitrobenzoic acid there was obtained 2(RS)- N- N- N- N- N-(4-acetamido-3-nitrobenzoyl)-L-α-aspartyl!-L-.alpha.-glutamyl!-2-methyl-L-phenylalanyl-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 979.4 M+H!.

EXAMPLE 57

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-glutamic acid and by replacing tert-butyl hydrogen succinate with 4-acetamidobenzoic acid there was obtained 2(RS)- N- N- N- N- N-(4-acetamidobenzoyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 934.4 M+H!.

EXAMPLE 58

In an analogous manner to Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-O-tert-L-α-glutamic acid and by replacing tert-butyl hydrogen succinate with 3,5-dichlorobenzoic acid there was obtained 2(RS)- N- N- N- N- N-(3,5-dichlorobenzoyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 945.3 M+H!.

EXAMPLE 59

0.78 g of 0.235 mmol/g 5- 2- 1(RS)- N- (9-fluorenyl)-methoxycarbonyl!-L-leucyl!amino!propyl!-4(RS),5,5-trimethyl-1,3,2-dioxoborolan-4-yl!-3(RS)-methyl-N- a(RS)-(4-methylphenyl)benzyl!valeramide-polystyrene conjugate was swollen in dimethylformamide for 20 minutes and then suspended and agitated in dimethylformamide/piperidine (4:1). After 5 minutes the resin was drained and then resuspended in and agitated with dimethylformamide/ piperidine (4:1) for a further five minutes. The resin was then drained and washed five times with dimethylformamide.

The resin was then suspended in a solution of 0.4 g, 1.08 mmol of N- (9-fluorenyl)methoxycarbonyl!-3-methyl-L-valine in dimethylformamide and then a mixture of 0.42 g (1.08 mmol) 2-(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 0.25ml (2.2 mmol) of N-methylmorpholine dissolved in dimethylformamide was added. After agitating for 40 minutes the resin was drained and washed five times with dimethylformamide.

The resin was resuspended in and agitated with dimethylformamide/piperidine(4:1). After 5 minutes the resin was drained, resuspended in and agitated with dimethylformamide/piperidine (4:1) for a further 5 minutes. Then the resin was drained and washed five times with dimethyl formamide.

The resin was then suspended in a solution of 0.44 g (1.08 mmol) of N- (9-fluorenyl)methoxycarbonyl!-3-(2-methylphenyl)-L-alanine in dimethylformamide and then a mixture of 0.42g 2-(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 0.25ml (2.2 mmol) of N-methylmorpholine dissolved in dimethylformamide was added. After agitating for 40 minutes the resin was drained and washed five times with dimethylformamide.

The resin was resuspended in and agitated with dimethylformamide/piperidine(4:1). After 5 minutes the resin was drained, resuspended in and agitated with dimethylformamide/piperidine (4:1) for a further 5 minutes. Then the resin was drained and washed five times with dimethyl formamide.

The resin was then suspended in a solution of 0.37 g (1.08 mmol) of N- (9-fluorenyl)methoxycarbonyl!-D-valine in dimethylformamide and then a mixture of 0.42 g of 2-(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 0.25 ml (2.2 mmol) of N-methylmorpholine dissolved in dimethylformamide was added. After agitating for 40 minutes the resin was drained and washed five times with dimethylformamide.

The resin was resuspended in and agitated with 0.7 ml of dimethylformamide/piperidine (4:1). After 5 minutes the resin was drained,resuspended in and agitated with dimethylformamide/piperidine (4:1) for a further 5 minutes. Then, the resin was drained and washed five times with 1 ml of dimethylformamide.

98 mg of this resin were then suspended in a solution of 0.06 g (0.19 mmol)of N-(benzyloxycarbonyl)-O-tert-butyl-L-α-aspartic acid in dimethylformamide and then a mixture of 0.06 g (0.19 mmol) of 2-(1 H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate and 0.1 ml (0.88 mmol) of N-methylmorpholine dissolved in dimethylformamide was added. After agitating for 40 minutes the resin was drained and washed three times with dimethylformamide, three times with ethyl acetate and three times with dichloromethane.

1 ml of dichloromethane was added to the resin which was then treated with 3 ml of a 9:1 mixture of trifluoroacetic acid and water and then agitated for 30 minutes. The resin was then filtered off and washed with dichloromethane. The filtrate and washings were combined and evaporated and then co-evaporated with toluene. The residue was triturated with diethyl ether and dried. There were obtained 12 mg of 1(RS)- N- N- N- N- N-(benzyloxycarbonyl)-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!propylboronic acid; MS: m/e 821.4 M+H-H₂ O!⁺.

EXAMPLE 60

200 mg (0.18 mmol) of N2- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 4-fluoro-1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl!-L-leucinamide were dissolved in 4.75 ml of trifluoroacetic acid and 0.25 ml of water. 2 ml of dichloromethane were added and the solution was stirred at room temperature for 3 hours. The solution was diluted with toluene and evaporated. The residue was triturated with diethyl ether and the resulting solid was filtered off and dried to give 95 mg of 4-fluoro-1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!butylboronic acid; MS: m/e 849.4 M+H-H₂ O!⁺.

The starting material was prepared as follows:

i) 2.5 ml (25 mmol) of borane-dimethyl sulphide (1:1) complex were dissolved in 50 ml of dimethoxyethane and the solution was cooled to 0° C. under nitrogen. 5.3 ml (52.5 mmol) of cyclohexene were then added. The solution was stirred at 0° C. for 15 minutes, then at room temperature for 1 hour and then cooled to -10° C. 1.6 g (27 mmol) of 3-fluoropropene were condensed and then added to the foregoing solution which was then stirred at room temperature under a dry ice condenser. After 1 hour the condenser was removed and stirring was continued for a further 1 hour. 3.9 g (52 mmol) of trimethylamine N-oxide were added and the solution was stirred for 1 hour. 3.1 g (26.3 mmol) of 2,3-dimethyl-2,3-butanediol were added and the solution was stirred for 16hours. The solution was evaporated and the residue was distilled. The distillate boiling at 35°-65° C./1 mm Hg was collected and purified by chromatography on silica gel using diethyl ether/ hexane (1:9)for the elution to give 1.67 g of 4,4,5,5-tetramethyl-2-(3-fluoropropyl)-1,3,2-dioxaborolane as a colourlessoil; ¹ H NMR (250 MHz, CDCl₃) δ: 0.75-0.85 (m, 2 H), 1.25 (s, 12 H), 1.7-1.9 (m, 2 H), 4.28 (t, 1 H), 4.48 (t, 1 H).

ii) 1.3 ml (8.8 mmol) of diisopropylamine and 5.5 ml (8.8 mmol) of butyllithium in hexane were added to 7 ml of tetrahydrofuran at -78° C. The cooled solution was added to a solution of 1.65 g (8.8 mmol) of 4,4,5,5-tetramethyl-2-(3-fluoropropyl)-1,3,2-dioxaborolane in 0.7ml of dichloromethane, 15 ml of cyclohexane and 8 ml of tetrahydrofuran at -20° C. under nitrogen. The solution was then stirred for 16 hours while slowly warming to room temperature. The solution was partitioned between 2M hydrochloric acid, brine and ethyl acetate, and the aqueous layer was extracted with ethyl acetate. The organic extracts were combined, washed with brine and dried over sodium sulphate. After evaporation the residue was purified by chromatography on silica gel usingdiethyl ether/hexane (1:9) for the elution to give 1.0 g of 2-(4-fluoro-1(RS)-chlorobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as a colourless oil; ¹ H NMR (250 MHz, CDCl₃) δ: 0.75-0.85 (m, 2 H), 1.3 (s, 12 H), 1.9-2.1 (m, 2 H), 3.45 (m, 1 H) 4.35 (m, 1 H), 4.55 (m, 1 H).

iii) 4.2 ml (4.2 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise to a solution of 1.0 g (4.2 mmol) of 2-(4-fluoro-1(RS)-chlorobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 7 ml of tetrahydrofuran under nitrogen at -78° C. The solution was then stirred overnight at room temperature. The solvent was removed by evaporation and the residue was taken up in diethyl ether. Insoluble material was removed by filtration and the solvent was removed by evaporation to give 1.53 g of material which was immediately redissolved in 7 ml of diethyl ether and cooled to 0° C. 0.95 ml (12.6 mmol) oftrifluoroacetic acid was added and the solution was stirred at 0° C.for 30 minutes. The solution was evaporated and the residue was evaporated with toluene to give 1.36 g of α(RS)-3-fluoropropyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate (1:1) as a brown oil which was used in the next step without further purification.

iv) 0.20 g (0.22 mmol) N- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine was dissolved in 2 ml of dimethylformamide and 4 ml of dichloromethane. 0.2 ml (1.52 mmol) of N-methylmorpholine was added and the solution was cooled to -10° C. under a nitrogen atmosphere. 40 mg (0.27 mmol) of isobutyl chloroformate were added and the solution was stirred for 10 minutes at -10° C. 0.2 g (0.44 mmol) of a(RS)-3-fluoropropyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylaminetrifluoroacetate (1:1) was added and the mixture was stirred at room temperature for 16 hours. Dichloromethane was added and the solution was washed with 2M hydrochloric acid and water and then dried over anhydrous sodium sulphate. After evaporation there was obtained 0.21 g of N2- N- N- N- N-(tert-butoxycarbonyl)-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N 1- 4-fluoro-1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)butyl!-L-leucinamide in the form of a solid; MS: m/e 1017.3 M+H-100!⁺.

EXAMPLE 61

In an analogous manner to that described in Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-glutamic acid and by replacing N- (9-fluorenyl)methoxycarbonyl!-2-methyl-L-phenylalanine with N- (9-fluorenyl)methoxycarbonyl!-4-chloro-L-phenylalanine there was obtained 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl-L-α-glutamyl!-4-chloro-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 893.3 M+H!.

EXAMPLE 62

In an analogous manner to that described in Example 4, by replacing N- (9-fluorenyl)methoxycarbonyl!-3-(2-naphthyl)-D-alanine with N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-glutamic acid, by replacing N- (9-fluorenyl)methoxycarbonyl!-O-tert-butyl-L-α-asparticacid with N-(benzyloxycarbonyl)-O-tert-butyl-L-α-aspartic acid and byomitting the reaction with tert-butyl succinate there was obtained 2(RS)- N- N- N- N- N-(benzyloxycarbonyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde as a white solid; MS: m/e 907.4 M+H!.

EXAMPLE 63

88 mg (0.09 mmol) of N2- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-4-chloro-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)-3-butenyl!-L-leucinamide were dissolved in ml of trifluoroacetic acid and 5 ml of dichloromethane. 5 drops of water were added and the solution was stirred at room temperature for 4 hours. The solution was diluted with toluene and evaporated. The residue was triturated with diethyl ether and the resulting solid was filtered offand dried to give 72 mg of 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-4-chloro-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-3-butenylboronic acid; MS: m/e 863 M+H-H₂ O!⁺.

The starting material was prepared as follows:

i) In an analogous manner to Example 1 iii)-x), by replacing N- (9-fluorenyl)methoxycarbonyl!-2-methyl-L-phenylalanine with N- (9-fluorenyl)methoxycarbonyl!-4-chloro-2-methyl-L-phenylalanine there was obtained N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-4-chloro-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine as a white solid; MS: m/e 952 M+H!⁺.

ii) 0.18 g (0.19 mmol) of N- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-4-chloro-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucine was dissolved in 2 ml of dimethylformamide and 5 ml of dichloromethane. 0.1 ml (0.94 mmol) of N-methylmorpholine was added and the solution was cooled to -15° C. under a nitrogen atmosphere. 35 mg (0.25 mmol) of isobutylchloroformate were added and the solution was stirred for 10 minutes at -10° C. 0.12 g (0.38 mmol) α(RS)-allyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate (1:1) was added and the mixture was stirred at room temperature for 2 hours. The solution was diluted with dichloromethane, washed with 2M hydrochloric acid and water and dried over anhydrous sodiumsulphate. After evaporation there was obtained 0.18 g of N2- N- N- N- N- 3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl!-O-tert-butyl-L-α-glutamyl!-4-chloro-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-butenyl!-L-leucinamide in the form of a white solid; MS: m/e 1131.6 M+H!⁺.

iii) 166 mg (0.147 mmol) of N2- N- N- N- N-(3-(tert-butoxycarbonyl)propionyl!-O-tert-butyl-L-α-aspartyl-O-tert-butyl-L-α-glutamyl!-4-chloro-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)-3-butenyl!-L-leucinamide were dissolved in 5 ml of trifluoroacetic acid and 5 ml of dichloromethane. The solution was stirred at room temperature for 30 minutes, then diluted with toluene and evaporated. The residue was triturated with ether and the resulting solid was filtered off, dried and then redissolved in 5 ml of trifluoroacetic acid and 5 ml of dichloromethane. The solution was stirred at room temperature for 30 minutes, diluted with toluene and evaporated. The residue was triturated with diethyl ether and the resulting solid was filtered off and dried to give 100 mg of N2- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-4-chloro-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-N1- 1(RS)-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)-3-butenyl!-L-leucinamide as a white solid; MS: m/e 863 M+H-100!⁺.

The following Examples illustrate pharmaceutical preparations containing compounds of formula I:

EXAMPLE A

Tablets containing the following ingredients may be produced in a conventional manner:

    ______________________________________     Ingredient        Per tablet     ______________________________________     Compound of formula I                       10.0        mg     Lactose           125.0       mg     Corn starch       75.0        mg     Talc              4.0         mg     Magnesium stearate                       1.0         mg     Total weight      215.0       mg     ______________________________________

EXAMPLE B

Capsules containing the following ingredients may be produced in a conventional manner:

    ______________________________________     Ingredient        Per capsule     ______________________________________     Compound of formula I                       10.0        mg     Lactose           165.0       mg     Corn starch       20.0        mg     Talc              5.0         mg     Capsule fill weight                       200.0       mg     ______________________________________

    __________________________________________________________________________     SEQUENCE LISTING     (1) GENERAL INFORMATION:     (iii) NUMBER OF SEQUENCES: 2     (2) INFORMATION FOR SEQ ID NO:1:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 7475 base pairs     (B) TYPE: nucleic acid     (C) STRANDEDNESS: double     (D) TOPOLOGY: circular     (ii) MOLECULE TYPE: DNA (genomic)     (iii) HYPOTHETICAL: NO     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:     CCGACACCATCGAATGGTGCAAAACCTTTCGCGGTATGGCATGATAGCGCCCGGAAGAGA60     GTCAATTCAGGGTGGTGAATGTGAAACCAGTAACGTTATACGATGTCGCAGAGTATGCCG120     GTGTCTCTTATCAGACCGTTTCCCGCGTGGTGAACCAGGCCAGCCACGTTTCTGCGAAAA180     CGCGGGAAAAAGTGGAAGCGGCGATGGCGGAGCTGAATTACATTCCCAACCGCGTGGCAC240     AACAACTGGCGGGCAAACAGTCGTTGCTGATTGGCGTTGCCACCTCCAGTCTGGCCCTGC300     ACGCGCCGTCGCAAATTGTCGCGGCGATTAAATCTCGCGCCGATCAACTGGGTGCCAGCG360     TGGTGGTGTCGATGGTAGAACGAAGCGGCGTCGAAGCCTGTAAAGCGGCGGTGCACAATC420     TTCTCGCGCAACGCGTCAGTGGGCTGATCATTAACTATCCGCTGGATGACCAGGATGCCA480     TTGCTGTGGAAGCTGCCTGCACTAATGTTCCGGCGTTATTTCTTGATGTCTCTGACCAGA540     CACCCATCAACAGTATTATTTTCTCCCATGAAGACGGTACGCGACTGGGCGTGGAGCATC600     TGGTCGCATTGGGTCACCAGCAAATCGCGCTGTTAGCGGGCCCATTAAGTTCTGTCTCGG660     CGCGTCTGCGTCTGGCTGGCTGGCATAAATATCTCACTCGCAATCAAATTCAGCCGATAG720     CGGAACGGGAAGGCGACTGGAGTGCCATGTCCGGTTTTCAACAAACCATGCAAATGCTGA780     ATGAGGGCATCGTTCCCACTGCGATGCTGGTTGCCAACGATCAGATGGCGCTGGGCGCAA840     TGCGCGCCATTACCGAGTCCGGGCTGCGCGTTGGTGCGGATATCTCGGTAGTGGGATACG900     ACGATACCGAAGACAGCTCATGTTATATCCCGCCGTTAACCACCATCAAACAGGATTTTC960     GCCTGCTGGGGCAAACCAGCGTGGACCGCTTGCTGCAACTCTCTCAGGGCCAGGCGGTGA1020     AGGGCAATCAGCTGTTGCCCGTCTCACTGGTGAAAAGAAAAACCACCCTGGCGCCCAATA1080     CGCAAACCGCCTCTCCCCGCGCGTTGGCCGATTCATTAATGCAGCTGGCACGACAGGTTT1140     CCCGACTGGAAAGCGGGCAGTGAGCGCAACGCAATTAATGTGAGTTAGCTCACTCATTAG1200     GCACAATTCTCATGTTTGACAGCTTATCATCGACTGCACGGTGCACCAATGCTTCTGGCG1260     TCAGGCAGCCATCGGAAGCTGTGGTATGGCTGTGCAGGTCGTAAATCACTGCATAATTCG1320     TGTCGCTCAAGGCGCACTCCCGTTCTGGATAATGTTTTTTGCGCCGACATCATAACGGTT1380     CTGGCAAATATTCTGAAATGAGCTGTTGACAATTAATCATCGGCTCGTATAATGTGTGGA1440     ATTGTGAGCGGATAACAATTTCACACAGGAAACAGCCAGTCCGTTTAGGTGTTTTCACGA1500     GCACTTCACCAACAAGGACCATAGATTATGAAAACTGAAGAAGGTAAACTGGTAATCTGG1560     ATTAACGGCGATAAAGGCTATAACGGTCTCGCTGAAGTCGGTAAGAAATTCGAGAAAGAT1620     ACCGGAATTAAAGTCACCGTTGAGCATCCGGATAAACTGGAAGAGAAATTCCCACAGGTT1680     GCGGCAACTGGCGATGGCCCTGACATTATCTTCTGGGCACACGACCGCTTTGGTGGCTAC1740     GCTCAATCTGGCCTGTTGGCTGAAATCACCCCGGACAAAGCGTTCCAGGACAAGCTGTAT1800     CCGTTTACCTGGGATGCCGTACGTTACAACGGCAAGCTGATTGCTTACCCGATCGCTGTT1860     GAAGCGTTATCGCTGATTTATAACAAAGATCTGCTGCCGAACCCGCCAAAAACCTGGGAA1920     GAGATCCCGGCGCTGGATAAAGAACTGAAAGCGAAAGGTAAGAGCGCGCTGATGTTCAAC1980     CTGCAAGAACCGTACTTCACCTGGCCGCTGATTGCTGCTGACGGGGGTTATGCGTTCAAG2040     TATGAAAACGGCAAGTACGACATTAAAGACGTGGGCGTGGATAACGCTGGCGCGAAAGCG2100     GGTCTGACCTTCCTGGTTGACCTGATTAAAAACAAACACATGAATGCAGACACCGATTAC2160     TCCATCGCAGAAGCTGCCTTTAATAAAGGCGAAACAGCGATGACCATCAACGGCCCGTGG2220     GCATGGTCCAACATCGACACCAGCAAAGTGAATTATGGTGTAACGGTACTGCCGACCTTC2280     AAGGGTCAACCATCCAAACCGTTCGTTGGCGTGCTGAGCGCAGGTATTAACGCCGCCAGT2340     CCGAACAAAGAGCTGGCAAAAGAGTTCCTCGAAAACTATCTGCTGACTGATGAAGGTCTG2400     GAAGCGGTTAATAAAGACAAACCGCTGGGTGCCGTAGCGCTGAAGTCTTACGAGGAAGAG2460     TTGGCGAAAGATCCACGTATTGCCGCCACCATGGAAAACGCCCAGAAAGGTGAAATCATG2520     CCGAACATCCCGCAGATGTCCGCTTTCTGGTATGCCGTGCGTACTGCGGTGATCAACGCC2580     GCCAGCGGTCGTCAGACTGTCGATGAAGCCCTGAAAGACGCGCAGACTAATTCGAGCTCG2640     AACAACAACAACAATAACAATAACAACAACCTCGGGATCGAGGGAAGGATTTCAGAATTC2700     ATGGGGAGGGAGATACATCTGGGACCGGCAGACAGCCTTGAAGGGCAGGGGTGGCGACTC2760     CTCGCGCATATTACGGCCTACTCTCAACAGACGCGGGGCCTACTTGGCTGCATCATCACT2820     AGCCTCACAGGCCGGGACAGGAACCAGGTCGAGGGGGAGGTCCAAATGGTCTCCACCGCA2880     ACACAATCTTTCCTGGCGACCTGCGTCAATGGCGTGTGTTGGACTGTCTATCATGGTGCC2940     GGCTCAAAGACCCTTGCCGGCCCAAAGGGCCCAATCACCCAAATGTACACCAATGTGGAC3000     CAGGACCTCGTCGGCTGGCAAGCGCCCCCCGGGGCGCGCTCCTTGACACCATGCACCTGC3060     GGCAGCTCAGACCTTTACTTGGTCACGAGGCATGCCGATGTCATTCCGGTGCGCCGGCGG3120     GGCGACAGCAGGGGAAGCCTACTCTCCCCCAGGCCCGTCTCCTACTTGAAGGGCTCTTCG3180     GGCGGTCCACTGCTCTGCCCCTCGGGGCACGCTGTGGGCATCTTCCGGGCTGCCGTGTGC3240     ACCCGAGGGGTTGCGAAGGCGGTGGACTTTGTACCCGTCGAGTCTATGGAAACCACTATG3300     CGGTCCCCGGTCTTCACGGACAACTCGTCCCCTCCGGCCGTATGCATGGGAGGAGGAGGA3360     GGAGGAGGAGGAGGAGGAGGAGGATCCATGAGCACCTGGGTGCTAGTAGGCGGAGTCCTA3420     GCAGCTCTGGCCGCGTATTGCCTGACAACAGGCAGCGTGGTCATTGTGGGCAGGATCGTC3480     TTGTCCGGAAAGCCGGCCATCATTCCCGACAGGGAAGTCCTCTACCGGGAGTTCGATGAG3540     ATGGAAGAGTGCTAGAAGCTTGGCACTGGCCGTCGTTTTACAACGTCGTGACTGGGAAAA3600     CCCTGGCGTTACCCAACTTAATCGCCTTGCAGCACATCCCCCTTTCGCCAGCTGGCGTAA3660     TAGCGAAGAGGCCCGCACCGATCGCCCTTCCCAACAGTTGCGCAGCCTGAATGGCGAATG3720     GCAGCTTGGCTGTTTTGGCGGATGAGATAAGATTTTCAGCCTGATACAGATTAAATCAGA3780     ACGCAGAAGCGGTCTGATAAAACAGAATTTGCCTGGCGGCAGTAGCGCGGTGGTCCCACC3840     TGACCCCATGCCGAACTCAGAAGTGAAACGCCGTAGCGCCGATGGTAGTGTGGGGTCTCC3900     CCATGCGAGAGTAGGGAACTGCCAGGCATCAAATAAAACGAAAGGCTCAGTCGAAAGACT3960     GGGCCTTTCGTTTTATCTGTTGTTTGTCGGTGAACGCTCTCCTGAGTAGGACAAATCCGC4020     CGGGAGCGGATTTGAACGTTGCGAAGCAACGGCCCGGAGGGTGGCGGGCAGGACGCCCGC4080     CATAAACTGCCAGGCATCAAATTAAGCAGAAGGCCATCCTGACGGATGGCCTTTTTGCGT4140     TTCTACAAACTCTTTTTGTTTATTTTTCTAAATACATTCAAATATGTATCCGCTCATGAG4200     ACAATAACCCTGATAAATGCTTCAATAATATTGAAAAAGGAAGAGTATGAGTATTCAACA4260     TTTCCGTGTCGCCCTTATTCCCTTTTTTGCGGCATTTTGCCTTCCTGTTTTTGCTCACCC4320     AGAAACGCTGGTGAAAGTAAAAGATGCTGAAGATCAGTTGGGTGCACGAGTGGGTTACAT4380     CGAACTGGATCTCAACAGCGGTAAGATCCTTGAGAGTTTTCGCCCCGAAGAACGTTCTCC4440     AATGATGAGCACTTTTAAAGTTCTGCTATGTGGCGCGGTATTATCCCGTGTTGACGCCGG4500     GCAAGAGCAACTCGGTCGCCGCATACACTATTCTCAGAATGACTTGGTTGAGTACTCACC4560     AGTCACAGAAAAGCATCTTACGGATGGCATGACAGTAAGAGAATTATGCAGTGCTGCCAT4620     AACCATGAGTGATAACACTGCGGCCAACTTACTTCTGACAACGATCGGAGGACCGAAGGA4680     GCTAACCGCTTTTTTGCACAACATGGGGGATCATGTAACTCGCCTTGATCGTTGGGAACC4740     GGAGCTGAATGAAGCCATACCAAACGACGAGCGTGACACCACGATGCCTGTAGCAATGGC4800     AACAACGTTGCGCAAACTATTAACTGGCGAACTACTTACTCTAGCTTCCCGGCAACAATT4860     AATAGACTGGATGGAGGCGGATAAAGTTGCAGGACCACTTCTGCGCTCGGCCCTTCCGGC4920     TGGCTGGTTTATTGCTGATAAATCTGGAGCCGGTGAGCGTGGGTCTCGCGGTATCATTGC4980     AGCACTGGGGCCAGATGGTAAGCCCTCCCGTATCGTAGTTATCTACACGACGGGGAGTCA5040     GGCAACTATGGATGAACGAAATAGACAGATCGCTGAGATAGGTGCCTCACTGATTAAGCA5100     TTGGTAACTGTCAGACCAAGTTTACTCATATATACTTTAGATTGATTTACCCCGGTTGAT5160     AATCAGAAAAGCCCCAAAAACAGGAAGATTGTATAAGCAAATATTTAAATTGTAAACGTT5220     AATATTTTGTTAAAATTCGCGTTAAATTTTTGTTAAATCAGCTCATTTTTTAACCAATAG5280     GCCGAAATCGGCAAAATCCCTTATAAATCAAAAGAATAGCCCGAGATAGGGTTGAGTGTT5340     GTTCCAGTTTGGAACAAGAGTCCACTATTAAAGAACGTGGACTCCAACGTCAAAGGGCGA5400     AAAACCGTCTATCAGGGCGATGGCCCACTACGTGAACCATCACCCAAATCAAGTTTTTTG5460     GGGTCGAGGTGCCGTAAAGCACTAAATCGGAACCCTAAAGGGAGCCCCCGATTTAGAGCT5520     TGACGGGGAAAGCCGGCGAACGTGGCGAGAAAGGAAGGGAAGAAAGCGAAAGGAGCGGGC5580     GCTAGGGCGCTGGCAAGTGTAGCGGTCACGCTGCGCGTAACCACCACACCCGCCGCGCTT5640     AATGCGCCGCTACAGGGCGCGTAAAAGGATCTAGGTGAAGATCCTTTTTGATAATCTCAT5700     GACCAAAATCCCTTAACGTGAGTTTTCGTTCCACTGAGCGTCAGACCCCGTAGAAAAGAT5760     CAAAGGATCTTCTTGAGATCCTTTTTTTCTGCGCGTAATCTGCTGCTTGCAAACAAAAAA5820     ACCACCGCTACCAGCGGTGGTTTGTTTGCCGGATCAAGAGCTACCAACTCTTTTTCCGAA5880     GGTAACTGGCTTCAGCAGAGCGCAGATACCAAATACTGTCCTTCTAGTGTAGCCGTAGTT5940     AGGCCACCACTTCAAGAACTCTGTAGCACCGCCTACATACCTCGCTCTGCTAATCCTGTT6000     ACCAGTGGCTGCTGCCAGTGGCGATAAGTCGTGTCTTACCGGGTTGGACTCAAGACGATA6060     GTTACCGGATAAGGCGCAGCGGTCGGGCTGAACGGGGGGTTCGTGCACACAGCCCAGCTT6120     GGAGCGAACGACCTACACCGAACTGAGATACCTACAGCGTGAGCTATGAGAAAGCGCCAC6180     GCTTCCCGAAGGGAGAAAGGCGGACAGGTATCCGGTAAGCGGCAGGGTCGGAACAGGAGA6240     GCGCACGAGGGAGCTTCCAGGGGGAAACGCCTGGTATCTTTATAGTCCTGTCGGGTTTCG6300     CCACCTCTGACTTGAGCGTCGATTTTTGTGATGCTCGTCAGGGGGGCGGAGCCTATGGAA6360     AAACGCCAGCAACGCGGCCTTTTTACGGTTCCTGGCCTTTTGCTGGCCTTTTGCTCACAT6420     GTTCTTTCCTGCGTTATCCCCTGATTCTGTGGATAACCGTATTACCGCCTTTGAGTGAGC6480     TGATACCGCTCGCCGCAGCCGAACGACCGAGCGCAGCGAGTCAGTGAGCGAGGAAGCGGA6540     AGAGCGCCTGATGCGGTATTTTCTCCTTACGCATCTGTGCGGTATTTCACACCGCATATG6600     GTGCACTCTCAGTACAATCTGCTCTGATGCCGCATAGTTAAGCCAGTATACACTCCGCTA6660     TCGCTACGTGACTGGGTCATGGCTGCGCCCCGACACCCGCCAACACCCGCTGACGCGCCC6720     TGACGGGCTTGTCTGCTCCCGGCATCCGCTTACAGACAAGCTGTGACCGTCTCCGGGAGC6780     TGCATGTGTCAGAGGTTTTCACCGTCATCACCGAAACGCGCGAGGCAGCTGCGGTAAAGC6840     TCATCAGCGTGGTCGTGCAGCGATTCACAGATGTCTGCCTGTTCATCCGCGTCCAGCTCG6900     TTGAGTTTCTCCAGAAGCGTTAATGTCTGGCTTCTGATAAAGCGGGCCATGTTAAGGGCG6960     GTTTTTTCCTGTTTGGTCACTTGATGCCTCCGTGTAAGGGGGAATTTCTGTTCATGGGGG7020     TAATGATACCGATGAAACGAGAGAGGATGCTCACGATACGGGTTACTGATGATGAACATG7080     CCCGGTTACTGGAACGTTGTGAGGGTAAACAACTGGCGGTATGGATGCGGCGGGACCAGA7140     GAAAAATCACTCAGGGTCAATGCCAGCGCTTCGTTAATACAGATGTAGGTGTTCCACAGG7200     GTAGCCAGCAGCATCCTGCGATGCAGATCCGGAACATAATGGTGCAGGGCGCTGACTTCC7260     GCGTTTCCAGACTTTACGAAACACGGAAACCGAAGACCATTCATGTTGTTGCTCAGGTCG7320     CAGACGTTTTGCAGCAGCAGTCGCTTCACGTTCGCTCGCGTATCGGTGATTCATTCTGCT7380     AACCAGTAAGGCAACCCCGCCAGCCTAGCCGGGTCCTCAACGACAGGAGCACGATCATGC7440     GCACCCGTGGCCAGGACCCAACGCTGCCCGAAATT7475     (2) INFORMATION FOR SEQ ID NO:2:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 675 amino acids     (B) TYPE: amino acid     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: protein     (iii) HYPOTHETICAL: NO     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:     MetLysThrGluGluGlyLysLeuValIleTrpIleAsnGlyAspLys     151015     GlyTyrAsnGlyLeuAlaGluValGlyLysLysPheGluLysAspThr     202530     GlyIleLysValThrValGluHisProAspLysLeuGluGluLysPhe     354045     ProGlnValAlaAlaThrGlyAspGlyProAspIleIlePheTrpAla     505560     HisAspArgPheGlyGlyTyrAlaGlnSerGlyLeuLeuAlaGluIle     65707580     ThrProAspLysAlaPheGlnAspLysLeuTyrProPheThrTrpAsp     859095     AlaValArgTyrAsnGlyLysLeuIleAlaTyrProIleAlaValGlu     100105110     AlaLeuSerLeuIleTyrAsnLysAspLeuLeuProAsnProProLys     115120125     ThrTrpGluGluIleProAlaLeuAspLysGluLeuLysAlaLysGly     130135140     LysSerAlaLeuMetPheAsnLeuGlnGluProTyrPheThrTrpPro     145150155160     LeuIleAlaAlaAspGlyGlyTyrAlaPheLysTyrGluAsnGlyLys     165170175     TyrAspIleLysAspValGlyValAspAsnAlaGlyAlaLysAlaGly     180185190     LeuThrPheLeuValAspLeuIleLysAsnLysHisMetAsnAlaAsp     195200205     ThrAspTyrSerIleAlaGluAlaAlaPheAsnLysGlyGluThrAla     210215220     MetThrIleAsnGlyProTrpAlaTrpSerAsnIleAspThrSerLys     225230235240     ValAsnTyrGlyValThrValLeuProThrPheLysGlyGlnProSer     245250255     LysProPheValGlyValLeuSerAlaGlyIleAsnAlaAlaSerPro     260265270     AsnLysGluLeuAlaLysGluPheLeuGluAsnTyrLeuLeuThrAsp     275280285     GluGlyLeuGluAlaValAsnLysAspLysProLeuGlyAlaValAla     290295300     LeuLysSerTyrGluGluGluLeuAlaLysAspProArgIleAlaAla     305310315320     ThrMetGluAsnAlaGlnLysGlyGluIleMetProAsnIleProGln     325330335     MetSerAlaPheTrpTyrAlaValArgThrAlaValIleAsnAlaAla     340345350     SerGlyArgGlnThrValAspGluAlaLeuLysAspAlaGlnThrAsn     355360365     SerSerSerAsnAsnAsnAsnAsnAsnAsnAsnAsnAsnLeuGlyIle     370375380     GluGlyArgIleSerGluPheMetGlyArgGluIleHisLeuGlyPro     385390395400     AlaAspSerLeuGluGlyGlnGlyTrpArgLeuLeuAlaHisIleThr     405410415     AlaTyrSerGlnGlnThrArgGlyLeuLeuGlyCysIleIleThrSer     420425430     LeuThrGlyArgAspArgAsnGlnValGluGlyGluValGlnMetVal     435440445     SerThrAlaThrGlnSerPheLeuAlaThrCysValAsnGlyValCys     450455460     TrpThrValTyrHisGlyAlaGlySerLysThrLeuAlaGlyProLys     465470475480     GlyProIleThrGlnMetTyrThrAsnValAspGlnAspLeuValGly     485490495     TrpGlnAlaProProGlyAlaArgSerLeuThrProCysThrCysGly     500505510     SerSerAspLeuTyrLeuValThrArgHisAlaAspValIleProVal     515520525     ArgArgArgGlyAspSerArgGlySerLeuLeuSerProArgProVal     530535540     SerTyrLeuLysGlySerSerGlyGlyProLeuLeuCysProSerGly     545550555560     HisAlaValGlyIlePheArgAlaAlaValCysThrArgGlyValAla     565570575     LysAlaValAspPheValProValGluSerMetGluThrThrMetArg     580585590     SerProValPheThrAspAsnSerSerProProAlaValCysMetGly     595600605     GlyGlyGlyGlyGlyGlyGlyGlyGlyGlyGlySerMetSerThrTrp     610615620     ValLeuValGlyGlyValLeuAlaAlaLeuAlaAlaTyrCysLeuThr     625630635640     ThrGlySerValValIleValGlyArgIleValLeuSerGlyLysPro     645650655     AlaIleIleProAspArgGluValLeuTyrArgGluPheAspGluMet     660665670     GluGluCys     675     __________________________________________________________________________ 

What is claimed is:
 1. A compound of the formula ##STR23## wherein E is CHO or B(OH)₂ ;R¹ is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl; R² is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and R³ is hydrogen or lower alkyl; or R² and R³ together are di- or trimethylene optionally substituted by hydroxy; R⁴ is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, lower alkenyl, aryl or lower cycloalkyl; R⁵ is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl; R⁶ is hydrogen or lower alkyl; R⁷ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl; R⁸ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl; and R⁹ is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower allkysulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl,or a salt of an acidic compound thereof with a base.
 2. The compound of claim 1, wherein R¹ is lower alkyl, halo-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl.
 3. The compound of claim 2, wherein the halo-lower alkyl is fluoro-lower alkyl.
 4. The compound of claim 2, wherein the heteroaryl-lower alkyl is thienyl-lower alkyl or furyl-lower alkyl.
 5. The compound of claim 1, wherein R² is lower alkyl, lower cycloalkyl-lower alkyl or aryl-lower alkyl.
 6. The compound of claim 1 wherein R³ is hydrogen.
 7. The compound of claim 1 wherein R² and R³ together are trimethylene optionally substituted by hydroxy.
 8. The compound of claim 1 wherein R⁴ is lower alkyl, lower cycloalkyl-lower alkyl, aryl-lower alkyl, aryl or lower cycloalkyl.
 9. The compound of claim 1 wherein R⁵ is aryl-lower alkyl or lower cycloalkyl.
 10. The compound of claim 1 wherein R⁶ is hydrogen.
 11. The compound claim 1 wherein R⁷ is lower alkyl, carboxy-lower alkyl, aryl-lower alkyl or hydroxy-lower alkyl.
 12. The compound of claim 1 wherein R⁸ is hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl.
 13. The compound of claim 1 wherein R⁹ is lower alkylcarbonyl or carboxy-lower alkylcarbonyl.
 14. The compound of claim 1, 2(S)- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!butyraldehyde.
 15. The compound of claim 1, 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4,4,-difluorovaleraldehyde.
 16. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4,4,4-trifluorobutyraldehyde.
 17. The compound of claim 1, 2(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α- glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-3-(methylthio)propionaldehyde.
 18. The compound of claim 1, 2(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-3-(butylthio)propionaldehyde.
 19. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4-pentenaldehyde.
 20. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4-pentynal.
 21. The compound of claim 1, 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4-hexynal.
 22. The compound of claim 1, 3-(benzylthio)-2(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!propionaldehyde.
 23. The compound of claim 1, 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-3-(2-thienyl)propionaldehyde.
 24. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-3-(3-thienyl)propionaldehyde.
 25. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-3-(2-naphthyl)-D-alanyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4,4,4-trifluorobutyraldehyde.
 26. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-seryl-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl!amino!-4,4,4-trifluorobutyraldehyde.
 27. The compound of claim 1, 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!hexanal.
 28. The compound of claim 1, (Z)-2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-.alpha.-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4-hexenal.
 29. The compound of claim 1, 2(RS)- N- N- N- N- N-(benzyloxycarbonyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4,4,4-trifluorobutyraldehyde.
 30. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-4-chloro-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4,4,4-trifluorobutyraldehyde.
 31. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4,4,4-trifluorobutyraldehyde.
 32. The compound of claim 1, 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-5-methylhexanal.
 33. The compound of claim 1, 2(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-5-hexenal.
 34. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-norleucyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4,4,4-trifluorobutyraldehyde.
 35. The compound of claim 1, 2(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-D-2-cyclohexylglycyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4,4,4-trifluorobutyraldehyde.
 36. The compound of claim 1, 2(RS)- N- N- N- N- N-(4-acetamidobenzoyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-4,4,4-trifluorobutyraldehyde.
 37. The compound of claim 1, 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!propylboronic acid.
 38. The compound of claim 1, 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!butylboronic acid.
 39. The compound of claim 1, 1(S)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-3-butenylboronic acid.
 40. The compound of claim 1, 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-4-chloro-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!-3-butenylboronic acid.
 41. The compound of claim 1, 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-3-cycopentyl-L-alanyl!amino!-3-butenylboronic acid.
 42. The compound of claim 1, 1(R)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl!-L-leucyl! amino!pentylboronic acid.
 43. The compound of claim 1, 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-2-methyl-L-phenylalanyl!-L-2-cyclohexylglycyl!-L-leucyl!amino!propylboronic acid.
 44. The compound of claim 1, 1(RS)- N- N- N- N- N-(3-carboxypropionyl)-L-α-aspartyl!-L-α-glutamyl!-L-2-cyclohexylglycyl!-3-methyl-L-valyl!-L-leucyl! amino!propylboronic acid.
 45. The compound of claim 1, 1(RS)- N- N- N- N- N-(benzyloxycarbonyl)-L-α-aspartyl!-D-valyl!-2-methyl-L-phenylalanyl!-3-methyl-L-valyl-L-leucyl!amino! propylboronic acid.
 46. A pharmaceutical composition comprising from ten to five hundred milligrams of a compound of claim 1 and a compatible pharmaceutical carrier.
 47. A compound of the formula ##STR24## wherein R¹ is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl;R² is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and R³ is hydrogen or lower alkyl; or R² and R³ together are di- or trimethylene optionally substituted by hydroxy; R⁴ is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, lower alkenyl, aryl or lower cycloalkyl; R⁵ is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl; R⁶ is hydrogen or lower alkyl; R⁷ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl; R⁸ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl; R⁹ is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl; and R¹⁰ and R¹ l are each independently a lower alkyl, and wherein any carboxy, hydroxy or aminocarbonyl group present in the compound is protected.
 48. A process for producing a compound of the formula: ##STR25## wherein E is CHO;R¹ is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl; R² is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and R³ is hydrogen or lower alkyl; or R² and R³ together are di- or trimethylene optionally substituted by hydroxy; R⁴ is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, lower alkenyl, aryl or lower cycloalkyl; R⁵ is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl; R⁶ is hydrogen or lower alkyl; R⁷ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl; R⁸ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl; and R⁹ is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl;which process comprises treating an acetal of the formula ##STR26## wherein any carboxy, hydroxy or aminocarbonyl group present in the acetal is protected, and R¹⁰ and R¹¹ are each independently a lower alkyl; with a strong acid, thereby producing the compound.
 49. The process of claim 48, further comprising treating the compound, wherein the compound is acidic, with a base, thereby producing a salt of the compound.
 50. The process of claim 49 wherein the acetal of formula II is bonded to a solid phase peptide synthesis resin.
 51. A process for producing a compound of the formula ##STR27## wherein E is B(OH)₂ R¹ is lower alkyl, halo-lower alkyl, cyano-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, aryl-lower alkyl, heteroaryl-lower alkyl, lower alkenyl or lower alkynyl; R² is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, aminocarbonyl-lower alkyl or lower cycloalkyl-lower alkyl; and R³ is hydrogen or lower alkyl; or R² and R³ together are di- or trimethylene optionally substituted by hydroxy; R⁴ is lower alkyl, hydroxy-lower alkyl, lower cycloalkyl-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl, aryl-lower alkylthio-lower alkyl, lower alkenyl, aryl or lower cycloalkyl; R⁵ is lower alkyl, hydroxy-lower alkyl, lower alkylthio-lower alkyl, aryl-lower alkyl, aryl-lower alkylthio-lower alkyl, cyano-lower alkylthio-lower alkyl or lower cycloalkyl; R⁶ is hydrogen or lower alkyl; R⁷ is lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl, aryl-lower alkyl, lower cycloalkyl-lower alkyl or lower cycloalkyl; R⁸ represents lower alkyl, hydroxy-lower alkyl, carboxy-lower alkyl or aryl-lower alkyl; and R⁹ is lower alkylcarbonyl, carboxy-lower alkylcarbonyl, arylcarbonyl, lower alkylsulphonyl, arylsulphonyl, lower alkoxycarbonyl or aryl-lower alkoxycarbonyl;which process comprises treating a substituted dioxaborolane of the formula ##STR28## wherein any carboxy, hydroxy or aminocarbonyl group present in the dioxaborolane is or is not protected, and Q is ##STR29## wherein R¹², R¹³, R¹⁴ and R¹⁵ each are hydrogen or lower alkyl and R¹⁶ and R¹⁷ each are hydrogen or lower alkyl, with a strong acid when Q is (a) and with an alkali metal periodate when Q is (b), thereby producing the compound.
 52. The process of claim 51, further comprising treating the compound, wherein the compound is acidic, with a base, thereby producing a salt of the compound.
 53. The process of claim 51, wherein the substituted dioxaborolane of formula III in which Q is a group of formula (a) is bonded to a solid phase peptide synthesis resin. 